From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Use ARCH_INIT_USER_COMPAT_FP_FRAME to describe how frame pointers are unwound on x86, and implement the hooks needed to add the segment base addresses. Enable HAVE_UNWIND_USER_COMPAT_FP if the system has compat mode compiled in. Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> --- Changes since v10: https://lore.kernel.org/20250611010430.123232579@xxxxxxxxxxx - Moved calling the functions arch_unwind_user_init() and arch_unwind_user_next() to this commit as it's the first commit to use them. (Peter Zijlstra) arch/x86/Kconfig | 1 + arch/x86/include/asm/unwind_user.h | 49 ++++++++++++++++++++++++ arch/x86/include/asm/unwind_user_types.h | 17 ++++++++ include/linux/unwind_user.h | 20 ++++++++++ kernel/unwind/user.c | 4 ++ 5 files changed, 91 insertions(+) create mode 100644 arch/x86/include/asm/unwind_user_types.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2cdb5cf91541..3f7bdc9e3cec 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -302,6 +302,7 @@ config X86 select HAVE_SYSCALL_TRACEPOINTS select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL select HAVE_UNSTABLE_SCHED_CLOCK + select HAVE_UNWIND_USER_COMPAT_FP if IA32_EMULATION select HAVE_UNWIND_USER_FP if X86_64 select HAVE_USER_RETURN_NOTIFIER select HAVE_GENERIC_VDSO diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h index 8597857bf896..43f8554c1d70 100644 --- a/arch/x86/include/asm/unwind_user.h +++ b/arch/x86/include/asm/unwind_user.h @@ -2,10 +2,59 @@ #ifndef _ASM_X86_UNWIND_USER_H #define _ASM_X86_UNWIND_USER_H +#include <linux/unwind_user_types.h> +#include <asm/ptrace.h> + #define ARCH_INIT_USER_FP_FRAME \ .cfa_off = (s32)sizeof(long) * 2, \ .ra_off = (s32)sizeof(long) * -1, \ .fp_off = (s32)sizeof(long) * -2, \ .use_fp = true, +#ifdef CONFIG_IA32_EMULATION + +#define ARCH_INIT_USER_COMPAT_FP_FRAME \ + .cfa_off = (s32)sizeof(u32) * 2, \ + .ra_off = (s32)sizeof(u32) * -1, \ + .fp_off = (s32)sizeof(u32) * -2, \ + .use_fp = true, + +#define in_compat_mode(regs) !user_64bit_mode(regs) + +static inline void arch_unwind_user_init(struct unwind_user_state *state, + struct pt_regs *regs) +{ + unsigned long cs_base, ss_base; + + if (state->type != UNWIND_USER_TYPE_COMPAT_FP) + return; + + scoped_guard(irqsave) { + cs_base = segment_base_address(regs->cs); + ss_base = segment_base_address(regs->ss); + } + + state->arch.cs_base = cs_base; + state->arch.ss_base = ss_base; + + state->ip += cs_base; + state->sp += ss_base; + state->fp += ss_base; +} +#define arch_unwind_user_init arch_unwind_user_init + +static inline void arch_unwind_user_next(struct unwind_user_state *state) +{ + if (state->type != UNWIND_USER_TYPE_COMPAT_FP) + return; + + state->ip += state->arch.cs_base; + state->fp += state->arch.ss_base; +} +#define arch_unwind_user_next arch_unwind_user_next + +#endif /* CONFIG_IA32_EMULATION */ + +#include <asm-generic/unwind_user.h> + #endif /* _ASM_X86_UNWIND_USER_H */ diff --git a/arch/x86/include/asm/unwind_user_types.h b/arch/x86/include/asm/unwind_user_types.h new file mode 100644 index 000000000000..d7074dc5f0ce --- /dev/null +++ b/arch/x86/include/asm/unwind_user_types.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_UNWIND_USER_TYPES_H +#define _ASM_UNWIND_USER_TYPES_H + +#ifdef CONFIG_IA32_EMULATION + +struct arch_unwind_user_state { + unsigned long ss_base; + unsigned long cs_base; +}; +#define arch_unwind_user_state arch_unwind_user_state + +#endif /* CONFIG_IA32_EMULATION */ + +#include <asm-generic/unwind_user_types.h> + +#endif /* _ASM_UNWIND_USER_TYPES_H */ diff --git a/include/linux/unwind_user.h b/include/linux/unwind_user.h index ac007363820a..46f995cda606 100644 --- a/include/linux/unwind_user.h +++ b/include/linux/unwind_user.h @@ -14,6 +14,26 @@ #define in_compat_mode(regs) false #endif +/* + * If an architecture needs to initialize the state for a specific + * reason, for example, it may need to do something different + * in compat mode, it can define arch_unwind_user_init to a + * function that will perform this initialization. + */ +#ifndef arch_unwind_user_init +static inline void arch_unwind_user_init(struct unwind_user_state *state, struct pt_regs *reg) {} +#endif + +/* + * If an architecture requires some more updates to the state between + * stack frames, it can define arch_unwind_user_next to a function + * that will update the state between reading stack frames during + * the user space stack walk. + */ +#ifndef arch_unwind_user_next +static inline void arch_unwind_user_next(struct unwind_user_state *state) {} +#endif + int unwind_user_start(struct unwind_user_state *state); int unwind_user_next(struct unwind_user_state *state); diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c index 3a0ac4346f5b..2bb7995c3f23 100644 --- a/kernel/unwind/user.c +++ b/kernel/unwind/user.c @@ -72,6 +72,8 @@ int unwind_user_next(struct unwind_user_state *state) if (frame->fp_off) state->fp = fp; + arch_unwind_user_next(state); + return 0; done: @@ -101,6 +103,8 @@ int unwind_user_start(struct unwind_user_state *state) state->sp = user_stack_pointer(regs); state->fp = frame_pointer(regs); + arch_unwind_user_init(state, regs); + return 0; } -- 2.47.2
