Merge tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "There's a bunch of fixes/cleanups throughout the tree as usual, but we
  also have a handful of new features:

   - Various improvements to the extension detection and alternative
     patching infrastructure

   - Zbb-optimized string routines

   - Support for cpu-capacity in the RISC-V DT bindings

   - Zicbom no longer depends on toolchain support

   - Some performance and code size improvements to ftrace

   - Support for ARCH_WANT_LD_ORPHAN_WARN

   - Oops now contain the faulting instruction"

* tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (67 commits)
  RISC-V: add a spin_shadow_stack declaration
  riscv: mm: hugetlb: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
  riscv: Add header include guards to insn.h
  riscv: alternative: proceed one more instruction for auipc/jalr pair
  riscv: Avoid enabling interrupts in die()
  riscv, mm: Perform BPF exhandler fixup on page fault
  RISC-V: take text_mutex during alternative patching
  riscv: hwcap: Don't alphabetize ISA extension IDs
  RISC-V: fix ordering of Zbb extension
  riscv: jump_label: Fixup unaligned arch_static_branch function
  RISC-V: Only provide the single-letter extensions in HWCAP
  riscv: mm: fix regression due to update_mmu_cache change
  scripts/decodecode: Add support for RISC-V
  riscv: Add instruction dump to RISC-V splats
  riscv: select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL
  riscv: vmlinux.lds.S: explicitly catch .init.bss sections from EFI stub
  riscv: vmlinux.lds.S: explicitly catch .riscv.attributes sections
  riscv: vmlinux.lds.S: explicitly catch .rela.dyn symbols
  riscv: lds: define RUNTIME_DISCARD_EXIT
  RISC-V: move some stray __RISCV_INSN_FUNCS definitions from kprobes
  ...

1 files changed, 39 insertions, 15 deletions

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 1b9a5a66e55a..8400f0cc9704 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -144,30 +144,54 @@ arch_initcall(riscv_cpuinfo_init);
 		.uprop = #UPROP,				\
 		.isa_ext_id = EXTID,				\
 	}
+
 /*
- * Here are the ordering rules of extension naming defined by RISC-V
- * specification :
- * 1. All extensions should be separated from other multi-letter extensions
- *    by an underscore.
- * 2. The first letter following the 'Z' conventionally indicates the most
+ * The canonical order of ISA extension names in the ISA string is defined in
+ * chapter 27 of the unprivileged specification.
+ *
+ * Ordinarily, for in-kernel data structures, this order is unimportant but
+ * isa_ext_arr defines the order of the ISA string in /proc/cpuinfo.
+ *
+ * The specification uses vague wording, such as should, when it comes to
+ * ordering, so for our purposes the following rules apply:
+ *
+ * 1. All multi-letter extensions must be separated from other extensions by an
+ *    underscore.
+ *
+ * 2. Additional standard extensions (starting with 'Z') must be sorted after
+ *    single-letter extensions and before any higher-privileged extensions.
+
+ * 3. The first letter following the 'Z' conventionally indicates the most
  *    closely related alphabetical extension category, IMAFDQLCBKJTPVH.
- *    If multiple 'Z' extensions are named, they should be ordered first
- *    by category, then alphabetically within a category.
- * 3. Standard supervisor-level extensions (starts with 'S') should be
- *    listed after standard unprivileged extensions.  If multiple
- *    supervisor-level extensions are listed, they should be ordered
+ *    If multiple 'Z' extensions are named, they must be ordered first by
+ *    category, then alphabetically within a category.
+ *
+ * 3. Standard supervisor-level extensions (starting with 'S') must be listed
+ *    after standard unprivileged extensions.  If multiple supervisor-level
+ *    extensions are listed, they must be ordered alphabetically.
+ *
+ * 4. Standard machine-level extensions (starting with 'Zxm') must be listed
+ *    after any lower-privileged, standard extensions.  If multiple
+ *    machine-level extensions are listed, they must be ordered
  *    alphabetically.
- * 4. Non-standard extensions (starts with 'X') must be listed after all
- *    standard extensions. They must be separated from other multi-letter
- *    extensions by an underscore.
+ *
+ * 5. Non-standard extensions (starting with 'X') must be listed after all
+ *    standard extensions. If multiple non-standard extensions are listed, they
+ *    must be ordered alphabetically.
+ *
+ * An example string following the order is:
+ *    rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux
+ *
+ * New entries to this struct should follow the ordering rules described above.
  */
 static struct riscv_isa_ext_data isa_ext_arr[] = {
+	__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
+	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
+	__RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB),
 	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
 	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
 	__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
-	__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
-	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
 	__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
 };