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-rw-r--r--arch/arm/Kconfig13
-rw-r--r--arch/arm/include/asm/memory.h55
-rw-r--r--arch/arm/include/asm/module.h15
-rw-r--r--arch/arm/kernel/armksyms.c4
-rw-r--r--arch/arm/kernel/head.S68
-rw-r--r--arch/arm/kernel/module.c23
-rw-r--r--arch/arm/kernel/vmlinux.lds.S4
7 files changed, 167 insertions, 15 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5cff165b7eb0..4147f76e7988 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -191,6 +191,19 @@ config VECTORS_BASE
help
The base address of exception vectors.
+config ARM_PATCH_PHYS_VIRT
+ bool "Patch physical to virtual translations at runtime (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ depends on !XIP_KERNEL && !THUMB2_KERNEL && MMU
+ depends on !ARCH_MSM
+ depends on !ARCH_REALVIEW || !SPARSEMEM
+ help
+ Patch phys-to-virt translation functions at runtime according to
+ the position of the kernel in system memory.
+
+ This can only be used with non-XIP, non-Thumb2, MMU kernels where
+ the base of physical memory is at a 16MB boundary.
+
source "init/Kconfig"
source "kernel/Kconfig.freezer"
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 2efec578a62e..7197879e1cb7 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -24,8 +24,6 @@
*/
#define UL(x) _AC(x, UL)
-#define PHYS_OFFSET PLAT_PHYS_OFFSET
-
#ifdef CONFIG_MMU
/*
@@ -135,16 +133,6 @@
#endif
/*
- * Physical vs virtual RAM address space conversion. These are
- * private definitions which should NOT be used outside memory.h
- * files. Use virt_to_phys/phys_to_virt/__pa/__va instead.
- */
-#ifndef __virt_to_phys
-#define __virt_to_phys(x) ((x) - PAGE_OFFSET + PHYS_OFFSET)
-#define __phys_to_virt(x) ((x) - PHYS_OFFSET + PAGE_OFFSET)
-#endif
-
-/*
* Convert a physical address to a Page Frame Number and back
*/
#define __phys_to_pfn(paddr) ((paddr) >> PAGE_SHIFT)
@@ -159,6 +147,49 @@
#ifndef __ASSEMBLY__
/*
+ * Physical vs virtual RAM address space conversion. These are
+ * private definitions which should NOT be used outside memory.h
+ * files. Use virt_to_phys/phys_to_virt/__pa/__va instead.
+ */
+#ifndef __virt_to_phys
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+
+extern unsigned long __pv_phys_offset;
+#define PHYS_OFFSET __pv_phys_offset
+
+#define __pv_stub(from,to,instr) \
+ __asm__("@ __pv_stub\n" \
+ "1: " instr " %0, %1, %2\n" \
+ " .pushsection .pv_table,\"a\"\n" \
+ " .long 1b\n" \
+ " .popsection\n" \
+ : "=r" (to) \
+ : "r" (from), "I" (0x81000000))
+
+static inline unsigned long __virt_to_phys(unsigned long x)
+{
+ unsigned long t;
+ __pv_stub(x, t, "add");
+ return t;
+}
+
+static inline unsigned long __phys_to_virt(unsigned long x)
+{
+ unsigned long t;
+ __pv_stub(x, t, "sub");
+ return t;
+}
+#else
+#define __virt_to_phys(x) ((x) - PAGE_OFFSET + PHYS_OFFSET)
+#define __phys_to_virt(x) ((x) - PHYS_OFFSET + PAGE_OFFSET)
+#endif
+#endif
+
+#ifndef PHYS_OFFSET
+#define PHYS_OFFSET PLAT_PHYS_OFFSET
+#endif
+
+/*
* The DMA mask corresponding to the maximum bus address allocatable
* using GFP_DMA. The default here places no restriction on DMA
* allocations. This must be the smallest DMA mask in the system,
diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index 12c8e680cbff..d072c21332ee 100644
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -25,8 +25,19 @@ struct mod_arch_specific {
};
/*
- * Include the ARM architecture version.
+ * Add the ARM architecture version to the version magic string
*/
-#define MODULE_ARCH_VERMAGIC "ARMv" __stringify(__LINUX_ARM_ARCH__) " "
+#define MODULE_ARCH_VERMAGIC_ARMVSN "ARMv" __stringify(__LINUX_ARM_ARCH__) " "
+
+/* Add __virt_to_phys patching state as well */
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+#define MODULE_ARCH_VERMAGIC_P2V "p2v8 "
+#else
+#define MODULE_ARCH_VERMAGIC_P2V ""
+#endif
+
+#define MODULE_ARCH_VERMAGIC \
+ MODULE_ARCH_VERMAGIC_ARMVSN \
+ MODULE_ARCH_VERMAGIC_P2V
#endif /* _ASM_ARM_MODULE_H */
diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index e5e1e5387678..9615423c37dd 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -170,3 +170,7 @@ EXPORT_SYMBOL(mcount);
#endif
EXPORT_SYMBOL(__gnu_mcount_nc);
#endif
+
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+EXPORT_SYMBOL(__pv_phys_offset);
+#endif
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 03a588b6e15c..1db8ead2e331 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -98,6 +98,9 @@ ENTRY(stext)
#ifdef CONFIG_SMP_ON_UP
bl __fixup_smp
#endif
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+ bl __fixup_pv_table
+#endif
bl __create_page_tables
/*
@@ -438,4 +441,69 @@ smp_on_up:
#endif
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+
+/* __fixup_pv_table - patch the stub instructions with the delta between
+ * PHYS_OFFSET and PAGE_OFFSET, which is assumed to be 16MiB aligned and
+ * can be expressed by an immediate shifter operand. The stub instruction
+ * has a form of '(add|sub) rd, rn, #imm'.
+ */
+ __HEAD
+__fixup_pv_table:
+ adr r0, 1f
+ ldmia r0, {r3-r5, r7}
+ sub r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET
+ add r4, r4, r3 @ adjust table start address
+ add r5, r5, r3 @ adjust table end address
+ str r8, [r7, r3]! @ save computed PHYS_OFFSET to __pv_phys_offset
+ mov r6, r3, lsr #24 @ constant for add/sub instructions
+ teq r3, r6, lsl #24 @ must be 16MiB aligned
+ bne __error
+ str r6, [r7, #4] @ save to __pv_offset
+ b __fixup_a_pv_table
+ENDPROC(__fixup_pv_table)
+
+ .align
+1: .long .
+ .long __pv_table_begin
+ .long __pv_table_end
+2: .long __pv_phys_offset
+
+ .text
+__fixup_a_pv_table:
+ b 3f
+2: ldr ip, [r7, r3]
+ bic ip, ip, #0x000000ff
+ orr ip, ip, r6
+ str ip, [r7, r3]
+3: cmp r4, r5
+ ldrcc r7, [r4], #4 @ use branch for delay slot
+ bcc 2b
+ mov pc, lr
+ENDPROC(__fixup_a_pv_table)
+
+ENTRY(fixup_pv_table)
+ stmfd sp!, {r4 - r7, lr}
+ ldr r2, 2f @ get address of __pv_phys_offset
+ mov r3, #0 @ no offset
+ mov r4, r0 @ r0 = table start
+ add r5, r0, r1 @ r1 = table size
+ ldr r6, [r2, #4] @ get __pv_offset
+ bl __fixup_a_pv_table
+ ldmfd sp!, {r4 - r7, pc}
+ENDPROC(fixup_pv_table)
+
+ .align
+2: .long __pv_phys_offset
+
+ .data
+ .globl __pv_phys_offset
+ .type __pv_phys_offset, %object
+__pv_phys_offset:
+ .long 0
+ .size __pv_phys_offset, . - __pv_phys_offset
+__pv_offset:
+ .long 0
+#endif
+
#include "head-common.S"
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 2cfe8161b478..c5679f6d9f64 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -268,12 +268,28 @@ struct mod_unwind_map {
const Elf_Shdr *txt_sec;
};
+static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
+ const Elf_Shdr *sechdrs, const char *name)
+{
+ const Elf_Shdr *s, *se;
+ const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+ for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
+ if (strcmp(name, secstrs + s->sh_name) == 0)
+ return s;
+
+ return NULL;
+}
+
+extern void fixup_pv_table(const void *, unsigned long);
+
int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
+ const Elf_Shdr *s = NULL;
#ifdef CONFIG_ARM_UNWIND
const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
- const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
+ const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
struct mod_unwind_map maps[ARM_SEC_MAX];
int i;
@@ -315,6 +331,11 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
maps[i].txt_sec->sh_addr,
maps[i].txt_sec->sh_size);
#endif
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+ s = find_mod_section(hdr, sechdrs, ".pv_table");
+ if (s)
+ fixup_pv_table((void *)s->sh_addr, s->sh_size);
+#endif
return 0;
}
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 86b66f3f2031..45b5651777ee 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -57,6 +57,10 @@ SECTIONS
__smpalt_end = .;
#endif
+ __pv_table_begin = .;
+ *(.pv_table)
+ __pv_table_end = .;
+
INIT_SETUP(16)
INIT_CALLS
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-04 08:29:49 +0000