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Subject[PATCH] powerpc/lib: Use patch_site to patch copy_32 functions once cache is enabled
Date
The symbol memcpy_nocache_branch defined in order to allow patching
of memset function once cache is enabled leads to confusing reports
by perf tool.

Using the new patch_site functionality solves this issue.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/asm-prototypes.h | 1 +
arch/powerpc/kernel/setup_32.c | 7 +++----
arch/powerpc/lib/copy_32.S | 9 ++++++---
3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index 70fdc5b9b9fb..1f4691ce4126 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -146,6 +146,7 @@ void _kvmppc_save_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr);
/* Patch sites */
extern s32 patch__call_flush_count_cache;
extern s32 patch__flush_count_cache_return;
+extern s32 patch__memset_nocache, patch__memcpy_nocache;

extern long flush_count_cache;

diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 0e3743343280..ba969278bf4d 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -97,11 +97,10 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
* We do the initial parsing of the flat device-tree and prepares
* for the MMU to be fully initialized.
*/
-extern unsigned int memset_nocache_branch; /* Insn to be replaced by NOP */
-
notrace void __init machine_init(u64 dt_ptr)
{
- unsigned int *addr = &memset_nocache_branch;
+ unsigned int *addr = (unsigned int *)((unsigned long)&patch__memset_nocache +
+ patch__memset_nocache);
unsigned long insn;

/* Configure static keys first, now that we're relocated. */
@@ -110,7 +109,7 @@ notrace void __init machine_init(u64 dt_ptr)
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();

- patch_instruction((unsigned int *)&memcpy, PPC_INST_NOP);
+ patch_instruction_site(&patch__memcpy_nocache, PPC_INST_NOP);

insn = create_cond_branch(addr, branch_target(addr), 0x820000);
patch_instruction(addr, insn); /* replace b by bne cr0 */
diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S
index da425bb6b369..ba66846fe973 100644
--- a/arch/powerpc/lib/copy_32.S
+++ b/arch/powerpc/lib/copy_32.S
@@ -13,6 +13,7 @@
#include <asm/errno.h>
#include <asm/ppc_asm.h>
#include <asm/export.h>
+#include <asm/code-patching-asm.h>

#define COPY_16_BYTES \
lwz r7,4(r4); \
@@ -107,8 +108,8 @@ _GLOBAL(memset)
* Skip optimised bloc until cache is enabled. Will be replaced
* by 'bne' during boot to use normal procedure if r4 is not zero
*/
-_GLOBAL(memset_nocache_branch)
- b 2f
+5: b 2f
+ patch_site 5b, patch__memset_nocache

clrlwi r7,r6,32-LG_CACHELINE_BYTES
add r8,r7,r5
@@ -168,7 +169,9 @@ _GLOBAL(memmove)
/* fall through */

_GLOBAL(memcpy)
- b generic_memcpy
+1: b generic_memcpy
+ patch_site 1b, patch__memcpy_nocache
+
add r7,r3,r5 /* test if the src & dst overlap */
add r8,r4,r5
cmplw 0,r4,r7
--
2.13.3
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