Implement inline static calls:
- Put a 'bl' to the destination function
- Put a 'nop' when the destination function is NULL
- Put a 'li r3,0' when the destination is the RET0 function
For the time being it only works if the destination is
within 32Mb from the caller.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/static_call.h | 2 +
arch/powerpc/kernel/static_call.c | 41 ++++++++++++-------
tools/objtool/arch/powerpc/include/arch/elf.h | 1 +
4 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5ef8bf8eb202..3257a1c258d8 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -246,6 +246,7 @@ config PPC
select HAVE_STACKPROTECTOR if PPC32 &&
$(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
select HAVE_STACKPROTECTOR if PPC64 &&
$(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
select HAVE_STATIC_CALL if PPC32
+ select HAVE_STATIC_CALL_INLINE if PPC32
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
select HUGETLB_PAGE_SIZE_VARIABLE if PPC_BOOK3S_64 && HUGETLB_PAGE
diff --git a/arch/powerpc/include/asm/static_call.h
b/arch/powerpc/include/asm/static_call.h
index de1018cc522b..e3d5d3823dac 100644
--- a/arch/powerpc/include/asm/static_call.h
+++ b/arch/powerpc/include/asm/static_call.h
@@ -26,4 +26,6 @@
#define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) __PPC_SCT(name, "blr")
#define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name) __PPC_SCT(name, "b
.+20")
+#define CALL_INSN_SIZE 4
+
#endif /* _ASM_POWERPC_STATIC_CALL_H */
diff --git a/arch/powerpc/kernel/static_call.c
b/arch/powerpc/kernel/static_call.c
index 863a7aa24650..fd25954cfd24 100644
--- a/arch/powerpc/kernel/static_call.c
+++ b/arch/powerpc/kernel/static_call.c
@@ -9,25 +9,38 @@ void arch_static_call_transform(void *site, void *tramp, void
*func, bool tail)
int err;
bool is_ret0 = (func == __static_call_return0);
unsigned long target = (unsigned long)(is_ret0 ? tramp + PPC_SCT_RET0 :
func);
- bool is_short = is_offset_in_branch_range((long)target - (long)tramp);
-
- if (!tramp)
- return;
mutex_lock(&text_mutex);
- if (func && !is_short) {
- err = patch_instruction(tramp + PPC_SCT_DATA, ppc_inst(target));
- if (err)
- goto out;
+ if (tramp) {
+ bool is_short = is_offset_in_branch_range((long)target -
(long)tramp);
+
+ if (func && !is_short) {
+ err = patch_instruction(tramp + PPC_SCT_DATA,
ppc_inst(target));
+ if (err)
+ goto out;
+ }
+
+ if (!func)
+ err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
+ else if (is_short)
+ err = patch_branch(tramp, target, 0);
+ else
+ err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
}
- if (!func)
- err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
- else if (is_short)
- err = patch_branch(tramp, target, 0);
- else
- err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
+ if (site) {
+ bool is_short = is_offset_in_branch_range((long)func -
(long)site);
+
+ if (!func)
+ err = patch_instruction(site, ppc_inst(PPC_RAW_NOP()));
+ else if (is_ret0)
+ err = patch_instruction(site, ppc_inst(PPC_RAW_LI(_R3,
0)));
+ else if (is_short)
+ err = patch_branch(site, target, BRANCH_SET_LINK);
+ else
+ panic("%s: function %pS is out of reach of %pS\n",
__func__, func, site);
+ }
out:
mutex_unlock(&text_mutex);
diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h
b/tools/objtool/arch/powerpc/include/arch/elf.h
index 3c8ebb7d2a6b..18784c764c14 100644
--- a/tools/objtool/arch/powerpc/include/arch/elf.h
+++ b/tools/objtool/arch/powerpc/include/arch/elf.h
@@ -4,5 +4,6 @@
#define _OBJTOOL_ARCH_ELF
#define R_NONE R_PPC_NONE
+#define R_REL32 R_PPC_REL32
#endif /* _OBJTOOL_ARCH_ELF */
--
2.35.3
