[PATCH v6 07/20] powerpc/8xx: Use patch_site for memory setup patching

From: Christophe Leroy
Date: Fri Oct 19 2018 - 02:55:10 EST


The 8xx TLB miss routines are patched at startup at several places.

This patch uses the new patch_site functionality in order
to get a better code readability and avoid a label mess when
dumping the code with 'objdump -d'

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 5 +++++
arch/powerpc/kernel/head_8xx.S | 19 +++++++++++--------
arch/powerpc/mm/8xx_mmu.c | 23 +++++++----------------
3 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index 193f53116c7a..3a15d6647d47 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -229,6 +229,11 @@ static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
BUG();
}

+/* patch sites */
+extern s32 patch__itlbmiss_linmem_top;
+extern s32 patch__dtlbmiss_linmem_top, patch__dtlbmiss_immr_jmp;
+extern s32 patch__fixupdar_linmem_top;
+
#endif /* !__ASSEMBLY__ */

#if defined(CONFIG_PPC_4K_PAGES)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 12c92a483fb1..0425571a533d 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -31,6 +31,7 @@
#include <asm/asm-offsets.h>
#include <asm/ptrace.h>
#include <asm/export.h>
+#include <asm/code-patching-asm.h>

#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000
/* By simply checking Address >= 0x80000000, we know if its a kernel address */
@@ -318,8 +319,8 @@ InstructionTLBMiss:
cmpli cr0, r11, PAGE_OFFSET@h
#ifndef CONFIG_PIN_TLB_TEXT
/* It is assumed that kernel code fits into the first 8M page */
-_ENTRY(ITLBMiss_cmp)
- cmpli cr7, r11, (PAGE_OFFSET + 0x0800000)@h
+0: cmpli cr7, r11, (PAGE_OFFSET + 0x0800000)@h
+ patch_site 0b, patch__itlbmiss_linmem_top
#endif
#endif
#endif
@@ -436,11 +437,11 @@ DataStoreTLBMiss:
#ifndef CONFIG_PIN_TLB_IMMR
cmpli cr0, r11, VIRT_IMMR_BASE@h
#endif
-_ENTRY(DTLBMiss_cmp)
- cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h
+0: cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h
+ patch_site 0b, patch__dtlbmiss_linmem_top
#ifndef CONFIG_PIN_TLB_IMMR
-_ENTRY(DTLBMiss_jmp)
- beq- DTLBMissIMMR
+0: beq- DTLBMissIMMR
+ patch_site 0b, patch__dtlbmiss_immr_jmp
#endif
blt cr7, DTLBMissLinear
lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
@@ -714,8 +715,10 @@ FixupDAR:/* Entry point for dcbx workaround. */
mfspr r11, SPRN_M_TW /* Get level 1 table */
blt+ 3f
rlwinm r11, r10, 16, 0xfff8
-_ENTRY(FixupDAR_cmp)
- cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h
+
+0: cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h
+ patch_site 0b, patch__fixupdar_linmem_top
+
/* create physical page address from effective address */
tophys(r11, r10)
blt- cr7, 201f
diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index fee599cf3bc3..d39f3af03221 100644
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c
@@ -97,22 +97,13 @@ static void __init mmu_mapin_immr(void)
map_kernel_page(v + offset, p + offset, PAGE_KERNEL_NCG);
}

-/* Address of instructions to patch */
-#ifndef CONFIG_PIN_TLB_IMMR
-extern unsigned int DTLBMiss_jmp;
-#endif
-extern unsigned int DTLBMiss_cmp, FixupDAR_cmp;
-#ifndef CONFIG_PIN_TLB_TEXT
-extern unsigned int ITLBMiss_cmp;
-#endif
-
-static void __init mmu_patch_cmp_limit(unsigned int *addr, unsigned long mapped)
+static void __init mmu_patch_cmp_limit(s32 *site, unsigned long mapped)
{
- unsigned int instr = *addr;
+ unsigned int instr = *(unsigned int *)site_addr(site);

instr &= 0xffff0000;
instr |= (unsigned long)__va(mapped) >> 16;
- patch_instruction(addr, instr);
+ patch_instruction_site(site, instr);
}

unsigned long __init mmu_mapin_ram(unsigned long top)
@@ -123,17 +114,17 @@ unsigned long __init mmu_mapin_ram(unsigned long top)
mapped = 0;
mmu_mapin_immr();
#ifndef CONFIG_PIN_TLB_IMMR
- patch_instruction(&DTLBMiss_jmp, PPC_INST_NOP);
+ patch_instruction_site(&patch__dtlbmiss_immr_jmp, PPC_INST_NOP);
#endif
#ifndef CONFIG_PIN_TLB_TEXT
- mmu_patch_cmp_limit(&ITLBMiss_cmp, 0);
+ mmu_patch_cmp_limit(&patch__itlbmiss_linmem_top, 0);
#endif
} else {
mapped = top & ~(LARGE_PAGE_SIZE_8M - 1);
}

- mmu_patch_cmp_limit(&DTLBMiss_cmp, mapped);
- mmu_patch_cmp_limit(&FixupDAR_cmp, mapped);
+ mmu_patch_cmp_limit(&patch__dtlbmiss_linmem_top, mapped);
+ mmu_patch_cmp_limit(&patch__fixupdar_linmem_top, mapped);

/* If the size of RAM is not an exact power of two, we may not
* have covered RAM in its entirety with 8 MiB
--
2.13.3