diff options
author | Zong Li | 2024-02-02 01:51:02 +0000 |
---|---|---|
committer | Palmer Dabbelt | 2024-02-22 12:17:47 -0800 |
commit | 680341382da56bd192ebfa4e58eaf4fec2e5bca7 (patch) | |
tree | 60f39c539e677ba1a1b17691ae9188abd503781c /arch/riscv | |
parent | 4af24146aa24d06f4594a427354f7ac878118d38 (diff) |
riscv: add CALLER_ADDRx support
CALLER_ADDRx returns caller's address at specified level, they are used
for several tracers. These macros eventually use
__builtin_return_address(n) to get the caller's address if arch doesn't
define their own implementation.
In RISC-V, __builtin_return_address(n) only works when n == 0, we need
to walk the stack frame to get the caller's address at specified level.
data.level started from 'level + 3' due to the call flow of getting
caller's address in RISC-V implementation. If we don't have additional
three iteration, the level is corresponding to follows:
callsite -> return_address -> arch_stack_walk -> walk_stackframe
| | | |
level 3 level 2 level 1 level 0
Fixes: 10626c32e382 ("riscv/ftrace: Add basic support")
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Link: https://lore.kernel.org/r/20240202015102.26251-1-zong.li@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r-- | arch/riscv/include/asm/ftrace.h | 5 | ||||
-rw-r--r-- | arch/riscv/kernel/Makefile | 2 | ||||
-rw-r--r-- | arch/riscv/kernel/return_address.c | 48 |
3 files changed, 55 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 329172122952..15055f9df4da 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -25,6 +25,11 @@ #define ARCH_SUPPORTS_FTRACE_OPS 1 #ifndef __ASSEMBLY__ + +extern void *return_address(unsigned int level); + +#define ftrace_return_address(n) return_address(n) + void MCOUNT_NAME(void); static inline unsigned long ftrace_call_adjust(unsigned long addr) { diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index f71910718053..604d6bf7e476 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -7,6 +7,7 @@ ifdef CONFIG_FTRACE CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_patch.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_sbi.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) endif CFLAGS_syscall_table.o += $(call cc-option,-Wno-override-init,) CFLAGS_compat_syscall_table.o += $(call cc-option,-Wno-override-init,) @@ -46,6 +47,7 @@ obj-y += irq.o obj-y += process.o obj-y += ptrace.o obj-y += reset.o +obj-y += return_address.o obj-y += setup.o obj-y += signal.o obj-y += syscall_table.o diff --git a/arch/riscv/kernel/return_address.c b/arch/riscv/kernel/return_address.c new file mode 100644 index 000000000000..c8115ec8fb30 --- /dev/null +++ b/arch/riscv/kernel/return_address.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This code come from arch/arm64/kernel/return_address.c + * + * Copyright (C) 2023 SiFive. + */ + +#include <linux/export.h> +#include <linux/kprobes.h> +#include <linux/stacktrace.h> + +struct return_address_data { + unsigned int level; + void *addr; +}; + +static bool save_return_addr(void *d, unsigned long pc) +{ + struct return_address_data *data = d; + + if (!data->level) { + data->addr = (void *)pc; + return false; + } + + --data->level; + + return true; +} +NOKPROBE_SYMBOL(save_return_addr); + +noinline void *return_address(unsigned int level) +{ + struct return_address_data data; + + data.level = level + 3; + data.addr = NULL; + + arch_stack_walk(save_return_addr, &data, current, NULL); + + if (!data.level) + return data.addr; + else + return NULL; + +} +EXPORT_SYMBOL_GPL(return_address); +NOKPROBE_SYMBOL(return_address); |