This add generic mmu_feature_enabled() function that get patched
to take right code path based on the feature bit enabled. The main
difference between the existing mmu_has_feature() function is the
hot patching using jump label framework.
The implementation wraps around mmu_has_feature so that we can use this
in early bootup code before we do the hotpatching.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/book3s/64/mmu.h | 2 +-
arch/powerpc/include/asm/mmu.h | 28 ++++++++++++++++++++++++
arch/powerpc/include/asm/synch.h | 1 +
arch/powerpc/kernel/module.c | 5 +++++
arch/powerpc/kernel/setup_64.c | 3 +++
arch/powerpc/kernel/vmlinux.lds.S | 7 ++++++
arch/powerpc/lib/feature-fixups.c | 37 ++++++++++++++++++++++++++++++++
7 files changed, 82 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h
b/arch/powerpc/include/asm/book3s/64/mmu.h
index 0835a8f9904b..696b7c5cc31f 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -23,7 +23,7 @@ struct mmu_psize_def {
};
extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
-#define radix_enabled() mmu_has_feature(MMU_FTR_RADIX)
+#define radix_enabled() mmu_feature_enabled(MMU_FTR_RADIX)
#endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 9e8c05f9c562..fdb70dc218e5 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -3,6 +3,7 @@
#ifdef __KERNEL__
#include <linux/types.h>
+#include <linux/jump_label.h>
#include <asm/asm-compat.h>
#include <asm/feature-fixups.h>
@@ -125,6 +126,7 @@ static inline void mmu_clear_feature(unsigned long feature)
}
extern unsigned int __start___mmu_ftr_fixup, __stop___mmu_ftr_fixup;
+extern unsigned int __start___mmu_ftr_fixup_c, __stop___mmu_ftr_fixup_c;
#ifdef CONFIG_PPC64
/* This is our real memory area size on ppc64 server, on embedded, we
@@ -142,6 +144,32 @@ static inline void assert_pte_locked(struct mm_struct *mm,
unsigned long addr)
}
#endif /* !CONFIG_DEBUG_VM */
+#ifdef HAVE_JUMP_LABEL
+static __always_inline bool mmu_feature_enabled(unsigned long feature)
+{
+ asm_volatile_goto("1:\n\t"
+ ".pushsection __mmu_ftr_fixup_c, \"a\"\n\t"
+ JUMP_ENTRY_TYPE "%0\n\t" /* feature bit */
+ JUMP_ENTRY_TYPE "1b\n\t"
+ JUMP_ENTRY_TYPE "%l[l_true]\n\t"
+ JUMP_ENTRY_TYPE "%l[l_false]\n\t"
+ ".popsection\n\t"
+ : : "i"(feature) : : l_true, l_false);
+ if (mmu_has_feature(feature))
+l_true:
+ return true;
+l_false:
+ return false;
+}
+#else
+static __always_inline bool mmu_feature_enabled(unsigned long feature)
+{
+ if (mmu_has_feature(feature))
+ return true;
+ return false;
+}
+#endif
+
#endif /* !__ASSEMBLY__ */
/* The kernel use the constants below to index in the page sizes array.
diff --git a/arch/powerpc/include/asm/synch.h b/arch/powerpc/include/asm/synch.h
index c50868681f9e..c34dd7ae176f 100644
--- a/arch/powerpc/include/asm/synch.h
+++ b/arch/powerpc/include/asm/synch.h
@@ -14,6 +14,7 @@ extern unsigned int __start___lwsync_fixup,
__stop___lwsync_fixup;
extern void do_lwsync_fixups(unsigned long value, void *fixup_start,
void *fixup_end);
extern void do_final_fixups(void);
+extern void do_feature_fixups_in_c(unsigned long value, void *fixup_start,
void *fixup_end);
static inline void eieio(void)
{
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index d1f1b35bf0c7..ea109d0b9494 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -80,5 +80,10 @@ int module_finalize(const Elf_Ehdr *hdr,
(void *)sect->sh_addr,
(void *)sect->sh_addr + sect->sh_size);
+ sect = find_section(hdr, sechdrs, "__mmu_ftr_fixup_c");
+ if (sect != NULL)
+ do_feature_fixups_in_c(cur_cpu_spec->mmu_features,
+ (void *)sect->sh_addr,
+ (void *)sect->sh_addr + sect->sh_size);
return 0;
}
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 5c03a6a9b054..79ab96ea7a6e 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -479,6 +479,9 @@ void __init setup_system(void)
&__start___mmu_ftr_fixup, &__stop___mmu_ftr_fixup);
do_feature_fixups(powerpc_firmware_features,
&__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
+ do_feature_fixups_in_c(cur_cpu_spec->mmu_features,
+ &__start___mmu_ftr_fixup_c,
+ &__stop___mmu_ftr_fixup_c);
do_lwsync_fixups(cur_cpu_spec->cpu_features,
&__start___lwsync_fixup, &__stop___lwsync_fixup);
do_final_fixups();
diff --git a/arch/powerpc/kernel/vmlinux.lds.S
b/arch/powerpc/kernel/vmlinux.lds.S
index d41fd0af8980..ffeed71987f6 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -147,6 +147,13 @@ SECTIONS
*(__fw_ftr_fixup)
__stop___fw_ftr_fixup = .;
}
+
+ . = ALIGN(8);
+ __mmu_ftr_fixup_c : AT(ADDR(__mmu_ftr_fixup_c) - LOAD_OFFSET) {
+ __start___mmu_ftr_fixup_c = .;
+ *(__mmu_ftr_fixup_c)
+ __stop___mmu_ftr_fixup_c = .;
+ }
#endif
.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
INIT_RAM_FS
diff --git a/arch/powerpc/lib/feature-fixups.c
b/arch/powerpc/lib/feature-fixups.c
index 7ce3870d7ddd..8e5fd8c71b0c 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -31,6 +31,13 @@ struct fixup_entry {
long alt_end_off;
};
+struct ftr_fixup_entry {
+ unsigned long feature_bit;
+ int *code;
+ unsigned long true_target;
+ unsigned long false_target;
+};
+
static unsigned int *calc_addr(struct fixup_entry *fcur, long offset)
{
/*
@@ -151,6 +158,36 @@ void do_final_fixups(void)
#endif
}
+void do_feature_fixups_in_c(unsigned long value, void *fixup_start,
+ void *fixup_end)
+{
+ unsigned long target;
+ struct ftr_fixup_entry *fcur, *fend;
+
+ fcur = fixup_start;
+ fend = fixup_end;
+
+ for (; fcur < fend; fcur++) {
+ if (fcur->code &&
+ kernel_text_address((unsigned long)fcur->code)) {
+ if (value & fcur->feature_bit)
+ target = fcur->true_target;
+ else
+ target = fcur->false_target;
+
+ /* Are we looping ? */
+ if ((unsigned long)fcur->code == target)
+ continue;
+
+ if (patch_branch(fcur->code, target, 0)) {
+ WARN_ON(1);
+ pr_err("Unable to patch radix section at %p\n",
+ fcur->code);
+ }
+ }
+ }
+}
+
#ifdef CONFIG_FTR_FIXUP_SELFTEST
#define check(x) \
--
2.7.4
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