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* riscv: dts: fu740: fix cache-controller interruptsDavid Abdurachmanov2021-06-191-1/+1
| | | | | | | | | | | | | | | The order of interrupt numbers is incorrect. The order for FU740 is: DirError, DataError, DataFail, DirFail From SiFive FU740-C000 Manual: 19 - L2 Cache DirError 20 - L2 Cache DirFail 21 - L2 Cache DataError 22 - L2 Cache DataFail Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: Ensure BPF_JIT_REGION_START aligned with PMD sizeJisheng Zhang2021-06-182-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andreas reported commit fc8504765ec5 ("riscv: bpf: Avoid breaking W^X") breaks booting with one kind of defconfig, I reproduced a kernel panic with the defconfig: [ 0.138553] Unable to handle kernel paging request at virtual address ffffffff81201220 [ 0.139159] Oops [#1] [ 0.139303] Modules linked in: [ 0.139601] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc5-default+ #1 [ 0.139934] Hardware name: riscv-virtio,qemu (DT) [ 0.140193] epc : __memset+0xc4/0xfc [ 0.140416] ra : skb_flow_dissector_init+0x1e/0x82 [ 0.140609] epc : ffffffff8029806c ra : ffffffff8033be78 sp : ffffffe001647da0 [ 0.140878] gp : ffffffff81134b08 tp : ffffffe001654380 t0 : ffffffff81201158 [ 0.141156] t1 : 0000000000000002 t2 : 0000000000000154 s0 : ffffffe001647dd0 [ 0.141424] s1 : ffffffff80a43250 a0 : ffffffff81201220 a1 : 0000000000000000 [ 0.141654] a2 : 000000000000003c a3 : ffffffff81201258 a4 : 0000000000000064 [ 0.141893] a5 : ffffffff8029806c a6 : 0000000000000040 a7 : ffffffffffffffff [ 0.142126] s2 : ffffffff81201220 s3 : 0000000000000009 s4 : ffffffff81135088 [ 0.142353] s5 : ffffffff81135038 s6 : ffffffff8080ce80 s7 : ffffffff80800438 [ 0.142584] s8 : ffffffff80bc6578 s9 : 0000000000000008 s10: ffffffff806000ac [ 0.142810] s11: 0000000000000000 t3 : fffffffffffffffc t4 : 0000000000000000 [ 0.143042] t5 : 0000000000000155 t6 : 00000000000003ff [ 0.143220] status: 0000000000000120 badaddr: ffffffff81201220 cause: 000000000000000f [ 0.143560] [<ffffffff8029806c>] __memset+0xc4/0xfc [ 0.143859] [<ffffffff8061e984>] init_default_flow_dissectors+0x22/0x60 [ 0.144092] [<ffffffff800010fc>] do_one_initcall+0x3e/0x168 [ 0.144278] [<ffffffff80600df0>] kernel_init_freeable+0x1c8/0x224 [ 0.144479] [<ffffffff804868a8>] kernel_init+0x12/0x110 [ 0.144658] [<ffffffff800022de>] ret_from_exception+0x0/0xc [ 0.145124] ---[ end trace f1e9643daa46d591 ]--- After some investigation, I think I found the root cause: commit 2bfc6cd81bd ("move kernel mapping outside of linear mapping") moves BPF JIT region after the kernel: | #define BPF_JIT_REGION_START PFN_ALIGN((unsigned long)&_end) The &_end is unlikely aligned with PMD size, so the front bpf jit region sits with part of kernel .data section in one PMD size mapping. But kernel is mapped in PMD SIZE, when bpf_jit_binary_lock_ro() is called to make the first bpf jit prog ROX, we will make part of kernel .data section RO too, so when we write to, for example memset the .data section, MMU will trigger a store page fault. To fix the issue, we need to ensure the BPF JIT region is PMD size aligned. This patch acchieve this goal by restoring the BPF JIT region to original position, I.E the 128MB before kernel .text section. The modification to kasan_init.c is inspired by Alexandre. Fixes: fc8504765ec5 ("riscv: bpf: Avoid breaking W^X") Reported-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: kasan: Fix MODULES_VADDR evaluation due to local variables' nameJisheng Zhang2021-06-181-4/+4
| | | | | | | | | | | | | | | | | commit 2bfc6cd81bd1 ("riscv: Move kernel mapping outside of linear mapping") makes use of MODULES_VADDR to populate kernel, BPF, modules mapping. Currently, MODULES_VADDR is defined as below for RV64: | #define MODULES_VADDR (PFN_ALIGN((unsigned long)&_end) - SZ_2G) But kasan_init() has two local variables which are also named as _start, _end, so MODULES_VADDR is evaluated with the local variable _end rather than the global "_end" as we expected. Fix this issue by renaming the two local variables. Fixes: 2bfc6cd81bd1 ("riscv: Move kernel mapping outside of linear mapping") Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: sifive: fix Kconfig errata warningRandy Dunlap2021-06-121-0/+1
| | | | | | | | | | | | | | | | | | | | | | The SOC_SIFIVE Kconfig entry unconditionally selects ERRATA_SIFIVE. However, ERRATA_SIFIVE depends on RISCV_ERRATA_ALTERNATIVE, which is not set, so SOC_SIFIVE should either depend on or select RISCV_ERRATA_ALTERNATIVE. Use 'select' here to quieten the Kconfig warning. WARNING: unmet direct dependencies detected for ERRATA_SIFIVE Depends on [n]: RISCV_ERRATA_ALTERNATIVE [=n] Selected by [y]: - SOC_SIFIVE [=y] Fixes: 1a0e5dbd3723 ("riscv: sifive: Add SiFive alternative ports") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: linux-riscv@lists.infradead.org Cc: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv32: Use medany C model for modulesKhem Raj2021-06-121-1/+1
| | | | | | | | | | | | When CONFIG_CMODEL_MEDLOW is used it ends up generating riscv_hi20_rela relocations in modules which are not resolved during runtime and following errors would be seen [ 4.802714] virtio_input: target 00000000c1539090 can not be addressed by the 32-bit offset from PC = 39148b7b [ 4.854800] virtio_input: target 00000000c1539090 can not be addressed by the 32-bit offset from PC = 9774456d Signed-off-by: Khem Raj <raj.khem@gmail.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: Fix BUILTIN_DTB for sifive and microchip socAlexandre Ghiti2021-06-112-0/+2
| | | | | | | | | | Fix BUILTIN_DTB config which resulted in a dtb that was actually not built into the Linux image: in the same manner as Canaan soc does, create an object file from the dtb file that will get linked into the Linux image. Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: alternative: fix typo in macro nameVitaly Wool2021-06-101-2/+2
| | | | | | | | | | | alternative-macros.h defines ALT_NEW_CONTENT in its assembly part and ALT_NEW_CONSTENT in the C part. Most likely it is the latter that is wrong. Fixes: 6f4eea90465ad (riscv: Introduce alternative mechanism to apply errata solution) Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: code patching only works on !XIP_KERNELJisheng Zhang2021-06-101-9/+9
| | | | | | | | | Some features which need code patching such as KPROBES, DYNAMIC_FTRACE KGDB can only work on !XIP_KERNEL. Add dependencies for these features that rely on code patching. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: xip: support runtime trap patchingVitaly Wool2021-06-102-5/+23
| | | | | | | | | | | | RISCV_ERRATA_ALTERNATIVE patches text at runtime which is currently not possible when the kernel is executed from the flash in XIP mode. Since runtime patching concerns only traps at the moment, let's just have all the traps reside in RAM anyway if RISCV_ERRATA_ALTERNATIVE is set. Thus, these functions will be patch-able even when the .text section is in flash. Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* Merge remote-tracking branch 'riscv/riscv-wx-mappings' into fixesPalmer Dabbelt2021-06-011-2/+6
|\ | | | | | | | | | | | | | | | | This single commit is shared between fixes and for-next, as it fixes a concrete bug while likely conflicting with a more invasive cleanup to avoid these oddball mappings entirely. * riscv/riscv-wx-mappings: riscv: mm: Fix W+X mappings at boot
| * riscv: mm: Fix W+X mappings at bootJisheng Zhang2021-06-011-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the kernel mapping was moved the last 2GB of the address space, (__va(PFN_PHYS(max_low_pfn))) is much smaller than the .data section start address, the last set_memory_nx() in protect_kernel_text_data() will fail, thus the .data section is still mapped as W+X. This results in below W+X mapping waring at boot. Fix it by passing the correct .data section page num to the set_memory_nx(). [ 0.396516] ------------[ cut here ]------------ [ 0.396889] riscv/mm: Found insecure W+X mapping at address (____ptrval____)/0xffffffff80c00000 [ 0.398347] WARNING: CPU: 0 PID: 1 at arch/riscv/mm/ptdump.c:258 note_page+0x244/0x24a [ 0.398964] Modules linked in: [ 0.399459] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc1+ #14 [ 0.400003] Hardware name: riscv-virtio,qemu (DT) [ 0.400591] epc : note_page+0x244/0x24a [ 0.401368] ra : note_page+0x244/0x24a [ 0.401772] epc : ffffffff80007c86 ra : ffffffff80007c86 sp : ffffffe000e7bc30 [ 0.402304] gp : ffffffff80caae88 tp : ffffffe000e70000 t0 : ffffffff80cb80cf [ 0.402800] t1 : ffffffff80cb80c0 t2 : 0000000000000000 s0 : ffffffe000e7bc80 [ 0.403310] s1 : ffffffe000e7bde8 a0 : 0000000000000053 a1 : ffffffff80c83ff0 [ 0.403805] a2 : 0000000000000010 a3 : 0000000000000000 a4 : 6c7e7a5137233100 [ 0.404298] a5 : 6c7e7a5137233100 a6 : 0000000000000030 a7 : ffffffffffffffff [ 0.404849] s2 : ffffffff80e00000 s3 : 0000000040000000 s4 : 0000000000000000 [ 0.405393] s5 : 0000000000000000 s6 : 0000000000000003 s7 : ffffffe000e7bd48 [ 0.405935] s8 : ffffffff81000000 s9 : ffffffffc0000000 s10: ffffffe000e7bd48 [ 0.406476] s11: 0000000000001000 t3 : 0000000000000072 t4 : ffffffffffffffff [ 0.407016] t5 : 0000000000000002 t6 : ffffffe000e7b978 [ 0.407435] status: 0000000000000120 badaddr: 0000000000000000 cause: 0000000000000003 [ 0.408052] Call Trace: [ 0.408343] [<ffffffff80007c86>] note_page+0x244/0x24a [ 0.408855] [<ffffffff8010c5a6>] ptdump_hole+0x14/0x1e [ 0.409263] [<ffffffff800f65c6>] walk_pgd_range+0x2a0/0x376 [ 0.409690] [<ffffffff800f6828>] walk_page_range_novma+0x4e/0x6e [ 0.410146] [<ffffffff8010c5f8>] ptdump_walk_pgd+0x48/0x78 [ 0.410570] [<ffffffff80007d66>] ptdump_check_wx+0xb4/0xf8 [ 0.410990] [<ffffffff80006738>] mark_rodata_ro+0x26/0x2e [ 0.411407] [<ffffffff8031961e>] kernel_init+0x44/0x108 [ 0.411814] [<ffffffff80002312>] ret_from_exception+0x0/0xc [ 0.412309] ---[ end trace 7ec3459f2547ea83 ]--- [ 0.413141] Checked W+X mappings: failed, 512 W+X pages found Fixes: 2bfc6cd81bd17e43 ("riscv: Move kernel mapping outside of linear mapping") Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | RISC-V: Fix memblock_free() usages in init_resources()Wende Tan2021-06-011-2/+2
| | | | | | | | | | | | | | | | | | | | `memblock_free()` takes a physical address as its first argument. Fix the wrong usages in `init_resources()`. Fixes: ffe0e526126884cf036a6f724220f1f9b4094fd2 ("RISC-V: Improve init_resources()") Fixes: 797f0375dd2ef5cdc68ac23450cbae9a5c67a74e ("RISC-V: Do not allocate memblock while iterating reserved memblocks") Signed-off-by: Wende Tan <twd2.me@gmail.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: skip errata_cip_453.o if CONFIG_ERRATA_SIFIVE_CIP_453 is disabledVincent2021-06-011-1/+1
| | | | | | | | | | | | | | | | | | | | The errata_cip_453.o should be built only when the Kconfig CONFIG_ERRATA_SIFIVE_CIP_453 is enabled. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Vincent <vincent.chen@sifive.com> Fixes: 0e0d4992517f ("riscv: enable SiFive errata CIP-453 and CIP-1200 Kconfig only if CONFIG_64BIT=y") Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: Use -mno-relax when using lld linkerKhem Raj2021-05-291-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lld does not implement the RISCV relaxation optimizations like GNU ld therefore disable it when building with lld, Also pass it to assembler when using external GNU assembler ( LLVM_IAS != 1 ), this ensures that relevant assembler option is also enabled along. if these options are not used then we see following relocations in objects 0000000000000000 R_RISCV_ALIGN *ABS*+0x0000000000000002 These are then rejected by lld ld.lld: error: capability.c:(.fixup+0x0): relocation R_RISCV_ALIGN requires unimplemented linker relaxation; recompile with -mno-relax but the .o is already compiled with -mno-relax Signed-off-by: Khem Raj <raj.khem@gmail.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: kexec: Fix W=1 build warningsJisheng Zhang2021-05-222-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes the following W=1 build warning(s): In file included from include/linux/kexec.h:28, from arch/riscv/kernel/machine_kexec.c:7: arch/riscv/include/asm/kexec.h:45:1: warning: ‘extern’ is not at beginning of declaration [-Wold-style-declaration] 45 | const extern unsigned char riscv_kexec_relocate[]; | ^~~~~ arch/riscv/include/asm/kexec.h:46:1: warning: ‘extern’ is not at beginning of declaration [-Wold-style-declaration] 46 | const extern unsigned int riscv_kexec_relocate_size; | ^~~~~ arch/riscv/kernel/machine_kexec.c:125:6: warning: no previous prototype for ‘machine_shutdown’ [-Wmissing-prototypes] 125 | void machine_shutdown(void) | ^~~~~~~~~~~~~~~~ arch/riscv/kernel/machine_kexec.c:147:1: warning: no previous prototype for ‘machine_crash_shutdown’ [-Wmissing-prototypes] 147 | machine_crash_shutdown(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~ arch/riscv/kernel/machine_kexec.c:23: warning: Function parameter or member 'image' not described in 'kexec_image_info' arch/riscv/kernel/machine_kexec.c:53: warning: Function parameter or member 'image' not described in 'machine_kexec_prepare' arch/riscv/kernel/machine_kexec.c:114: warning: Function parameter or member 'image' not described in 'machine_kexec_cleanup' arch/riscv/kernel/machine_kexec.c:148: warning: Function parameter or member 'regs' not described in 'machine_crash_shutdown' arch/riscv/kernel/machine_kexec.c:167: warning: Function parameter or member 'image' not described in 'machine_kexec' Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: kprobes: Fix build error when MMU=nJisheng Zhang2021-05-221-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lkp reported a randconfig failure: arch/riscv/kernel/probes/kprobes.c:90:22: error: use of undeclared identifier 'PAGE_KERNEL_READ_EXEC' We implemented the alloc_insn_page() to allocate PAGE_KERNEL_READ_EXEC page for kprobes insn page for STRICT_MODULE_RWX. But if MMU=n, we should fall back to the generic weak alloc_insn_page() by generic kprobe subsystem. Fixes: cdd1b2bd358f ("riscv: kprobes: Implement alloc_insn_page()") Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: Select ARCH_USE_MEMTESTKefeng Wang2021-05-221-0/+1
| | | | | | | | | | | | | | | | | | As of commit dce44566192e ("mm/memtest: add ARCH_USE_MEMTEST"), architectures must select ARCH_USE_MEMTESET to enable CONFIG_MEMTEST. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Fixes: f6e5aedf470b ("riscv: Add support for memtest") Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* | riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabledChen Huang2021-05-221-7/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | As [1] and [2] said, the arch_stack_walk should not to trace itself, or it will leave the trace unexpectedly when called. The example is when we do "cat /sys/kernel/debug/page_owner", all pages' stack is the same. arch_stack_walk+0x18/0x20 stack_trace_save+0x40/0x60 register_dummy_stack+0x24/0x5e init_page_owner+0x2e So we use __builtin_frame_address(1) as the first frame to be walked. And mark the arch_stack_walk() noinline. We found that pr_cont will affact pages' stack whose task state is RUNNING when testing "echo t > /proc/sysrq-trigger". So move the place of pr_cont and mark the function dump_backtrace() noinline. Also we move the case when task == NULL into else branch, and test for it in "echo c > /proc/sysrq-trigger". [1] https://lore.kernel.org/lkml/20210319184106.5688-1-mark.rutland@arm.com/ [2] https://lore.kernel.org/lkml/20210317142050.57712-1-chenjun102@huawei.com/ Signed-off-by: Chen Huang <chenhuang5@huawei.com> Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: remove unused handle_exception symbolRouven Czerwinski2021-05-061-2/+0
| | | | | | | | | Since commit 79b1feba5455 ("RISC-V: Setup exception vector early") exception vectors are setup early and the handle_exception symbol from the asm files is no longer referenced in traps.c. Remove it. Signed-off-by: Rouven Czerwinski <rouven@czerwinskis.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: Consistify protect_kernel_linear_mapping_text_rodata() useGeert Uytterhoeven2021-05-063-4/+7
| | | | | | | | | | | | | | | | | | | The various uses of protect_kernel_linear_mapping_text_rodata() are not consistent: - Its definition depends on "64BIT && !XIP_KERNEL", - Its forward declaration depends on MMU, - Its single caller depends on "STRICT_KERNEL_RWX && 64BIT && MMU && !XIP_KERNEL". Fix this by settling on the dependencies of the caller, which can be simplified as STRICT_KERNEL_RWX depends on "MMU && !XIP_KERNEL". Provide a dummy definition, as the caller is protected by "IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)" instead of "#ifdef CONFIG_STRICT_KERNEL_RWX". Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: enable SiFive errata CIP-453 and CIP-1200 Kconfig only if CONFIG_64BIT=yVincent Chen2021-05-061-2/+2
| | | | | | | | | | | | The corresponding hardware issues of CONFIG_ERRATA_SIFIVE_CIP_453 and CONFIG_ERRATA_SIFIVE_CIP_1200 only exist in the SiFive 64bit CPU cores. Therefore, these two errata are required only if CONFIG_64BIT=y Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Fixes: bff3ff525460 ("riscv: sifive: Apply errata "cip-1200" patch") Fixes: 800149a77c2c ("riscv: sifive: Apply errata "cip-453" patch") Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* riscv: Only extend kernel reservation if mapped read-onlyGeert Uytterhoeven2021-05-061-2/+7
| | | | | | | | | | | | | | | | | | | | When the kernel mapping was moved outside of the linear mapping, the kernel memory reservation was increased, to take into account mapping granularity. However, this is done unconditionally, regardless of whether the kernel memory is mapped read-only or not. If this extension is not needed, up to 2 MiB may be lost, which has a big impact on e.g. Canaan K210 (64-bit nommu) platforms with only 8 MiB of RAM. Reclaim the lost memory by only extending the reserved region when needed, i.e. depending on a simplified version of the conditional logic around the call to protect_kernel_linear_mapping_text_rodata(). Fixes: 2bfc6cd81bd17e43 ("riscv: Move kernel mapping outside of linear mapping") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* Merge tag 'riscv-for-linus-5.13-mw0' of ↵Linus Torvalds2021-05-0663-214/+2525
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V updates from Palmer Dabbelt: - Support for the memtest= kernel command-line argument. - Support for building the kernel with FORTIFY_SOURCE. - Support for generic clockevent broadcasts. - Support for the buildtar build target. - Some build system cleanups to pass more LLVM-friendly arguments. - Support for kprobes. - A rearranged kernel memory map, the first part of supporting sv48 systems. - Improvements to kexec, along with support for kdump and crash kernels. - An alternatives-based errata framework, along with support for handling a pair of errata that manifest on some SiFive designs (including the HiFive Unmatched). - Support for XIP. - A device tree for the Microchip PolarFire ICICLE SoC and associated dev board. ... along with a bunch of cleanups. There are already a handful of fixes on the list so there will likely be a part 2. * tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (45 commits) RISC-V: Always define XIP_FIXUP riscv: Remove 32b kernel mapping from page table dump riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=y RISC-V: Fix error code returned by riscv_hartid_to_cpuid() RISC-V: Enable Microchip PolarFire ICICLE SoC RISC-V: Initial DTS for Microchip ICICLE board dt-bindings: riscv: microchip: Add YAML documentation for the PolarFire SoC RISC-V: Add Microchip PolarFire SoC kconfig option RISC-V: enable XIP RISC-V: Add crash kernel support RISC-V: Add kdump support RISC-V: Improve init_resources() RISC-V: Add kexec support RISC-V: Add EM_RISCV to kexec UAPI header riscv: vdso: fix and clean-up Makefile riscv/mm: Use BUG_ON instead of if condition followed by BUG. riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMU riscv: module: Create module allocations without exec permissions riscv: bpf: Avoid breaking W^X ...
| * RISC-V: Always define XIP_FIXUPPalmer Dabbelt2021-05-011-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | XIP depends on MMU, but XIP_FIXUP is used throughout the kernel in order to avoid excessive ifdefs. This just makes sure to always define XIP_FIXUP, which will fix MMU=n builds. XIP_OFFSET is used by assembly but XIP_FIXUP is C-only, so they're split. Fixes: 44c922572952 ("RISC-V: enable XIP") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> Tested-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Remove 32b kernel mapping from page table dumpAlexandre Ghiti2021-05-011-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | The 32b kernel mapping lies in the linear mapping, there is no point in printing its address in page table dump, so remove this leftover that comes from moving the kernel mapping outside the linear mapping for 64b kernel. Fixes: e9efb21fe352 ("riscv: Prepare ptdump for vm layout dynamic addresses") Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=yAlexandre Ghiti2021-05-011-1/+1
| | | | | | | | | | | | | | | | | | Declare kernel_virt_addr for 32b kernel since it is used in __phys_addr_symbol defined when CONFIG_DEBUG_VIRTUAL is set. Fixes: 2bfc6cd81bd17 ("riscv: Move kernel mapping outside of linear mapping") Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Fix error code returned by riscv_hartid_to_cpuid()Anup Patel2021-05-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | We should return a negative error code upon failure in riscv_hartid_to_cpuid() instead of NR_CPUS. This is also aligned with all uses of riscv_hartid_to_cpuid() which expect negative error code upon failure. Fixes: 6825c7a80f18 ("RISC-V: Add logical CPU indexing for RISC-V") Fixes: f99fb607fb2b ("RISC-V: Use Linux logical CPU number instead of hartid") Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Enable Microchip PolarFire ICICLE SoCAtish Patra2021-04-261-0/+4
| | | | | | | | | | | | | | | | | | | | Enable Microchip PolarFire ICICLE soc config in defconfig. It allows the default upstream kernel to boot on PolarFire ICICLE board. Signed-off-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Bin Meng <bin.meng@windriver.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Initial DTS for Microchip ICICLE boardAtish Patra2021-04-264-0/+404
| | | | | | | | | | | | | | | | | | | | | | Add initial DTS for Microchip ICICLE board having only essential devices (clocks, sdhci, ethernet, serial, etc). The device tree is based on the U-Boot patch. https://patchwork.ozlabs.org/project/uboot/patch/20201110103414.10142-6-padmarao.begari@microchip.com/ Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Add Microchip PolarFire SoC kconfig optionAtish Patra2021-04-261-0/+7
| | | | | | | | | | | | | | | | | | | | Add Microchip PolarFire kconfig option which selects SoC specific and common drivers that is required for this SoC. Signed-off-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Bin Meng <bin.meng@windriver.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: enable XIPVitaly Wool2021-04-2611-19/+424
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce XIP (eXecute In Place) support for RISC-V platforms. It allows code to be executed directly from non-volatile storage directly addressable by the CPU, such as QSPI NOR flash which can be found on many RISC-V platforms. This makes way for significant optimization of RAM footprint. The XIP kernel is not compressed since it has to run directly from flash, so it will occupy more space on the non-volatile storage. The physical flash address used to link the kernel object files and for storing it has to be known at compile time and is represented by a Kconfig option. XIP on RISC-V will for the time being only work on MMU-enabled kernels. Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com> [Alex: Rebase on top of "Move kernel mapping outside the linear mapping" ] Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> [Palmer: disable XIP for allyesconfig] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Add crash kernel supportNick Kossifidis2021-04-265-0/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch allows Linux to act as a crash kernel for use with kdump. Userspace will let the crash kernel know about the memory region it can use through linux,usable-memory property on the /memory node (overriding its reg property), and about the memory region where the elf core header of the previous kernel is saved, through a reserved-memory node with a compatible string of "linux,elfcorehdr". This approach is the least invasive and re-uses functionality already present. I tested this on riscv64 qemu and it works as expected, you may test it by retrieving the dmesg of the previous kernel through /proc/vmcore, using the vmcore-dmesg utility from kexec-tools. Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Add kdump supportNick Kossifidis2021-04-268-27/+249
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds support for kdump, the kernel will reserve a region for the crash kernel and jump there on panic. In order for userspace tools (kexec-tools) to prepare the crash kernel kexec image, we also need to expose some information on /proc/iomem for the memory regions used by the kernel and for the region reserved for crash kernel. Note that on userspace the device tree is used to determine the system's memory layout so the "System RAM" on /proc/iomem is ignored. I tested this on riscv64 qemu and works as expected, you may test it by triggering a crash through /proc/sysrq_trigger: echo c > /proc/sysrq_trigger Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Improve init_resources()Nick Kossifidis2021-04-261-44/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel region is always present and we know where it is, no need to look for it inside the loop, just ignore it like the rest of the reserved regions within system's memory. Additionally, we don't need to call memblock_free inside the loop, as if called it'll split the region of pre-allocated resources in two parts, messing things up, just re-use the previous pre-allocated resource and free any unused resources after both loops finish. Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> [Palmer: commit text] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * RISC-V: Add kexec supportNick Kossifidis2021-04-265-0/+412
| | | | | | | | | | | | | | | | | | | | This patch adds support for kexec on RISC-V. On SMP systems it depends on HOTPLUG_CPU in order to be able to bring up all harts after kexec. It also needs a recent OpenSBI version that supports the HSM extension. I tested it on riscv64 QEMU on both an smp and a non-smp system. Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: vdso: fix and clean-up MakefileJisheng Zhang2021-04-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Running "make" on an already compiled kernel tree will rebuild the kernel even without any modifications: CALL linux/scripts/checksyscalls.sh CALL linux/scripts/atomic/check-atomics.sh CHK include/generated/compile.h SO2S arch/riscv/kernel/vdso/vdso-syms.S AS arch/riscv/kernel/vdso/vdso-syms.o AR arch/riscv/kernel/vdso/built-in.a AR arch/riscv/kernel/built-in.a AR arch/riscv/built-in.a GEN .version CHK include/generated/compile.h UPD include/generated/compile.h CC init/version.o AR init/built-in.a LD vmlinux.o The reason is "Any target that utilizes if_changed must be listed in $(targets), otherwise the command line check will fail, and the target will always be built" as explained by Documentation/kbuild/makefiles.rst Fix this build bug by adding vdso-syms.S to $(targets) At the same time, there are two trivial clean up modifications: - the vdso-dummy.o is not needed any more after so remove it. - vdso.lds is a generated file, so it should be prefixed with $(obj)/ instead of $(src)/ Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+") Cc: stable@vger.kernel.org Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv/mm: Use BUG_ON instead of if condition followed by BUG.zhouchuangao2021-04-261-2/+2
| | | | | | | | | | | | | | BUG_ON() uses unlikely in if(), which can be optimized at compile time. Signed-off-by: zhouchuangao <zhouchuangao@vivo.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobeLiao Chang2021-04-261-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The execution of sys_read end up hitting a BUG_ON() in __find_get_block after installing kprobe at sys_read, the BUG message like the following: [ 65.708663] ------------[ cut here ]------------ [ 65.709987] kernel BUG at fs/buffer.c:1251! [ 65.711283] Kernel BUG [#1] [ 65.712032] Modules linked in: [ 65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1 [ 65.714407] Hardware name: riscv-virtio,qemu (DT) [ 65.715696] epc : __find_get_block+0x218/0x2c8 [ 65.716835] ra : __getblk_gfp+0x1c/0x4a [ 65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930 [ 65.719553] gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038 [ 65.721290] t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960 [ 65.723051] s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a [ 65.724772] a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040 [ 65.726545] a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000 [ 65.728308] s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008 [ 65.730049] s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8 [ 65.731802] s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008 [ 65.733516] s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f [ 65.734434] t5 : 00000000000003ff t6 : 0000000000040000 [ 65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003 [ 65.734901] Call Trace: [ 65.735076] [<ffffffe00019f11e>] __find_get_block+0x218/0x2c8 [ 65.735417] [<ffffffe00020017a>] __ext4_get_inode_loc+0xb2/0x2f6 [ 65.735618] [<ffffffe000201b6c>] ext4_get_inode_loc+0x3a/0x8a [ 65.735802] [<ffffffe000203380>] ext4_reserve_inode_write+0x2e/0x8c [ 65.735999] [<ffffffe00020357a>] __ext4_mark_inode_dirty+0x4c/0x18e [ 65.736208] [<ffffffe000206bb0>] ext4_dirty_inode+0x46/0x66 [ 65.736387] [<ffffffe000192914>] __mark_inode_dirty+0x12c/0x3da [ 65.736576] [<ffffffe000180dd2>] touch_atime+0x146/0x150 [ 65.736748] [<ffffffe00010d762>] filemap_read+0x234/0x246 [ 65.736920] [<ffffffe00010d834>] generic_file_read_iter+0xc0/0x114 [ 65.737114] [<ffffffe0001f5d7a>] ext4_file_read_iter+0x42/0xea [ 65.737310] [<ffffffe000163f2c>] new_sync_read+0xe2/0x15a [ 65.737483] [<ffffffe000165814>] vfs_read+0xca/0xf2 [ 65.737641] [<ffffffe000165bae>] ksys_read+0x5e/0xc8 [ 65.737816] [<ffffffe000165c26>] sys_read+0xe/0x16 [ 65.737973] [<ffffffe000003972>] ret_from_syscall+0x0/0x2 [ 65.738858] ---[ end trace fe93f985456c935d ]--- A simple reproducer looks like: echo 'p:myprobe sys_read fd=%a0 buf=%a1 count=%a2' > /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable cat /sys/kernel/debug/tracing/trace Here's what happens to hit that BUG_ON(): 1) After installing kprobe at entry of sys_read, the first instruction is replaced by 'ebreak' instruction on riscv64 platform. 2) Once kernel reach the 'ebreak' instruction at the entry of sys_read, it trap into the riscv breakpoint handler, where it do something to setup for coming single-step of origin instruction, including backup the 'sstatus' in pt_regs, followed by disable interrupt during single stepping via clear 'SIE' bit of 'sstatus' in pt_regs. 3) Then kernel restore to the instruction slot contains two instructions, one is original instruction at entry of sys_read, the other is 'ebreak'. Here it trigger a 'Instruction page fault' exception (value at 'scause' is '0xc'), if PF is not filled into PageTabe for that slot yet. 4) Again kernel trap into page fault exception handler, where it choose different policy according to the state of running kprobe. Because afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kprobe and 'pc' points back to the probe address. 5) Because 'epc' point back to 'ebreak' instrution at sys_read probe, kernel trap into breakpoint handler again, and repeat the operations at 2), however 'sstatus' without 'SIE' is keep at 4), it cause the real 'sstatus' saved at 2) is overwritten by the one withou 'SIE'. 6) When kernel cross the probe the 'sstatus' CSR restore with value without 'SIE', and reach __find_get_block where it requires the interrupt must be enabled. Fix this is very trivial, just restore the value of 'sstatus' in pt_regs with backup one at 2) when the instruction being single stepped cause a page fault. Fixes: c22b0bcb1dd02 ("riscv: Add kprobes supported") Signed-off-by: Liao Chang <liaochang1@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMUJisheng Zhang2021-04-261-0/+1
| | | | | | | | | | | | | | | | Now we can set ARCH_HAS_STRICT_MODULE_RWX for MMU riscv platforms, this is good from security perspective. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: module: Create module allocations without exec permissionsJisheng Zhang2021-04-261-1/+1
| | | | | | | | | | | | | | | | | | The core code manages the executable permissions of code regions of modules explicitly, it is not necessary to create the module vmalloc regions with RWX permissions. Create them with RW- permissions instead. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: bpf: Avoid breaking W^XJisheng Zhang2021-04-261-1/+2
| | | | | | | | | | | | | | | | | | We allocate Non-executable pages, then call bpf_jit_binary_lock_ro() to enable executable permission after mapping them read-only. This is to prepare for STRICT_MODULE_RWX in following patch. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: bpf: Move bpf_jit_alloc_exec() and bpf_jit_free_exec() to coreJisheng Zhang2021-04-262-13/+13
| | | | | | | | | | | | | | | | | | | | | | We will drop the executable permissions of the code pages from the mapping at allocation time soon. Move bpf_jit_alloc_exec() and bpf_jit_free_exec() to bpf_jit_core.c so that they can be shared by both RV64I and RV32I. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Acked-by: Luke Nelson <luke.r.nels@gmail.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: kprobes: Implement alloc_insn_page()Jisheng Zhang2021-04-261-0/+8
| | | | | | | | | | | | | | | | Allocate PAGE_KERNEL_READ_EXEC(read only, executable) page for kprobes insn page. This is to prepare for STRICT_MODULE_RWX. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Constify sbi_ipi_opsJisheng Zhang2021-04-263-5/+5
| | | | | | | | | | | | | | | | | | Constify the sbi_ipi_ops so that it will be placed in the .rodata section. This will cause attempts to modify it to fail when strict page permissions are in place. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Constify sys_call_tableJisheng Zhang2021-04-262-2/+2
| | | | | | | | | | | | | | | | | | Constify the sys_call_table so that it will be placed in the .rodata section. This will cause attempts to modify the table to fail when strict page permissions are in place. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Mark some global variables __ro_after_initJisheng Zhang2021-04-265-12/+12
| | | | | | | | | | | | | | | | All of these are never modified after init, so they can be __ro_after_init. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: add __init section marker to some functionsJisheng Zhang2021-04-264-8/+8
| | | | | | | | | | | | | | | | They are not needed after booting, so mark them as __init to move them to the __init section. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Prepare ptdump for vm layout dynamic addressesAlexandre Ghiti2021-04-261-12/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a preparatory patch for sv48 support that will introduce dynamic PAGE_OFFSET. Dynamic PAGE_OFFSET implies that all zones (vmalloc, vmemmap, fixaddr...) whose addresses depend on PAGE_OFFSET become dynamic and can't be used to statically initialize the array used by ptdump to identify the different zones of the vm layout. Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Move kernel mapping outside of linear mappingAlexandre Ghiti2021-04-2612-36/+182
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a preparatory patch for relocatable kernel and sv48 support. The kernel used to be linked at PAGE_OFFSET address therefore we could use the linear mapping for the kernel mapping. But the relocated kernel base address will be different from PAGE_OFFSET and since in the linear mapping, two different virtual addresses cannot point to the same physical address, the kernel mapping needs to lie outside the linear mapping so that we don't have to copy it at the same physical offset. The kernel mapping is moved to the last 2GB of the address space, BPF is now always after the kernel and modules use the 2GB memory range right before the kernel, so BPF and modules regions do not overlap. KASLR implementation will simply have to move the kernel in the last 2GB range and just take care of leaving enough space for BPF. In addition, by moving the kernel to the end of the address space, both sv39 and sv48 kernels will be exactly the same without needing to be relocated at runtime. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> [Palmer: Squash the STRICT_RWX fix, and a !MMU fix] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| * riscv: Select HAVE_DYNAMIC_FTRACE when -fpatchable-function-entry is availableNathan Chancellor2021-04-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | clang prior to 13.0.0 does not support -fpatchable-function-entry for RISC-V. clang: error: unsupported option '-fpatchable-function-entry=8' for target 'riscv64-unknown-linux-gnu' To avoid this error, only select HAVE_DYNAMIC_FTRACE when this option is not available. Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") Link: https://github.com/ClangBuiltLinux/linux/issues/1268 Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>