diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/static_call.h | 28 | ||||
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/static_call.c | 37 |
4 files changed, 67 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index aac3437c8668..5d0586214662 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -243,6 +243,7 @@ config PPC select HAVE_SOFTIRQ_ON_OWN_STACK select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2) select HAVE_STACKPROTECTOR if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13) + select HAVE_STATIC_CALL if PPC32 select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING select HUGETLB_PAGE_SIZE_VARIABLE if PPC_BOOK3S_64 && HUGETLB_PAGE diff --git a/arch/powerpc/include/asm/static_call.h b/arch/powerpc/include/asm/static_call.h new file mode 100644 index 000000000000..0a0bc79bd1fa --- /dev/null +++ b/arch/powerpc/include/asm/static_call.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_STATIC_CALL_H +#define _ASM_POWERPC_STATIC_CALL_H + +#define __PPC_SCT(name, inst) \ + asm(".pushsection .text, \"ax\" \n" \ + ".align 5 \n" \ + ".globl " STATIC_CALL_TRAMP_STR(name) " \n" \ + STATIC_CALL_TRAMP_STR(name) ": \n" \ + inst " \n" \ + " lis 12,2f@ha \n" \ + " lwz 12,2f@l(12) \n" \ + " mtctr 12 \n" \ + " bctr \n" \ + "1: li 3, 0 \n" \ + " blr \n" \ + "2: .long 0 \n" \ + ".type " STATIC_CALL_TRAMP_STR(name) ", @function \n" \ + ".size " STATIC_CALL_TRAMP_STR(name) ", . - " STATIC_CALL_TRAMP_STR(name) " \n" \ + ".popsection \n") + +#define PPC_SCT_RET0 20 /* Offset of label 1 */ +#define PPC_SCT_DATA 28 /* Offset of label 2 */ + +#define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func) __PPC_SCT(name, "b " #func) +#define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) __PPC_SCT(name, "blr") + +#endif /* _ASM_POWERPC_STATIC_CALL_H */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 825121eba3c2..d079292525b6 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -106,7 +106,7 @@ extra-y += vmlinux.lds obj-$(CONFIG_RELOCATABLE) += reloc_$(BITS).o -obj-$(CONFIG_PPC32) += entry_32.o setup_32.o early_32.o +obj-$(CONFIG_PPC32) += entry_32.o setup_32.o early_32.o static_call.o obj-$(CONFIG_PPC64) += dma-iommu.o iommu.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_BOOTX_TEXT) += btext.o diff --git a/arch/powerpc/kernel/static_call.c b/arch/powerpc/kernel/static_call.c new file mode 100644 index 000000000000..863a7aa24650 --- /dev/null +++ b/arch/powerpc/kernel/static_call.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/memory.h> +#include <linux/static_call.h> + +#include <asm/code-patching.h> + +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 (!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())); +out: + mutex_unlock(&text_mutex); + + if (err) + panic("%s: patching failed %pS at %pS\n", __func__, func, tramp); +} +EXPORT_SYMBOL_GPL(arch_static_call_transform); |