From: Josh Poimboeuf <jpoim...@kernel.org> Add optional support for user space compat mode frame pointer unwinding. If supported, the arch needs to enable CONFIG_HAVE_UNWIND_USER_COMPAT_FP and define ARCH_INIT_USER_COMPAT_FP_FRAME.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org> Co-developed-by: Steven Rostedt (Google) <rost...@goodmis.org> Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org> --- Changes since v9: https://lore.kernel.org/linux-trace-kernel/20250513223551.459986...@goodmis.org/ As asm-generic headers are not included when an architecture defines the header, having more than one #ifndef and setting variables does not work with those checks in the asm-generic header and the architecture header does not define all the values. - Move #indef arch_unwind_user_state to linux/user_unwind_types.h - Move the following to linux/unwind_user.h: #ifndef ARCH_INIT_USER_COMPAT_FP_FRAME #ifndef arch_unwind_user_init #ifndef arch_unwind_user_next - Changed UNWIND_GET_USER_LONG() to use "unsigned long" instead of u64 as this can be called on 32 bit architectures and just because "compat_state()" returns false doesn't mean that the value is 64 bit. arch/Kconfig | 4 +++ include/asm-generic/Kbuild | 1 + include/asm-generic/unwind_user_types.h | 5 ++++ include/linux/unwind_user.h | 13 +++++++++ include/linux/unwind_user_types.h | 7 +++++ kernel/unwind/user.c | 36 ++++++++++++++++++++++--- 6 files changed, 62 insertions(+), 4 deletions(-) create mode 100644 include/asm-generic/unwind_user_types.h diff --git a/arch/Kconfig b/arch/Kconfig index 8e3fd723bd74..2c41d3072910 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -442,6 +442,10 @@ config HAVE_UNWIND_USER_FP bool select UNWIND_USER +config HAVE_UNWIND_USER_COMPAT_FP + bool + depends on HAVE_UNWIND_USER_FP + config HAVE_PERF_REGS bool help diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index 295c94a3ccc1..b797a2434396 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -60,6 +60,7 @@ mandatory-y += topology.h mandatory-y += trace_clock.h mandatory-y += uaccess.h mandatory-y += unwind_user.h +mandatory-y += unwind_user_types.h mandatory-y += vermagic.h mandatory-y += vga.h mandatory-y += video.h diff --git a/include/asm-generic/unwind_user_types.h b/include/asm-generic/unwind_user_types.h new file mode 100644 index 000000000000..f568b82e52cd --- /dev/null +++ b/include/asm-generic/unwind_user_types.h @@ -0,0 +1,5 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_UNWIND_USER_TYPES_H +#define _ASM_GENERIC_UNWIND_USER_TYPES_H + +#endif /* _ASM_GENERIC_UNWIND_USER_TYPES_H */ diff --git a/include/linux/unwind_user.h b/include/linux/unwind_user.h index a405111c41b0..c70da8f7e54c 100644 --- a/include/linux/unwind_user.h +++ b/include/linux/unwind_user.h @@ -9,6 +9,19 @@ #define ARCH_INIT_USER_FP_FRAME #endif +#ifndef ARCH_INIT_USER_COMPAT_FP_FRAME + #define ARCH_INIT_USER_COMPAT_FP_FRAME + #define in_compat_mode(regs) false +#endif + +#ifndef arch_unwind_user_init +static inline void arch_unwind_user_init(struct unwind_user_state *state, struct pt_regs *reg) {} +#endif + +#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/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h index 65bd070eb6b0..0b6563951ca4 100644 --- a/include/linux/unwind_user_types.h +++ b/include/linux/unwind_user_types.h @@ -3,10 +3,16 @@ #define _LINUX_UNWIND_USER_TYPES_H #include <linux/types.h> +#include <asm/unwind_user_types.h> + +#ifndef arch_unwind_user_state +struct arch_unwind_user_state {}; +#endif enum unwind_user_type { UNWIND_USER_TYPE_NONE, UNWIND_USER_TYPE_FP, + UNWIND_USER_TYPE_COMPAT_FP, }; struct unwind_stacktrace { @@ -25,6 +31,7 @@ struct unwind_user_state { unsigned long ip; unsigned long sp; unsigned long fp; + struct arch_unwind_user_state arch; enum unwind_user_type type; bool done; }; diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c index 4fc550356b33..29e1f497a26e 100644 --- a/kernel/unwind/user.c +++ b/kernel/unwind/user.c @@ -12,12 +12,32 @@ static struct unwind_user_frame fp_frame = { ARCH_INIT_USER_FP_FRAME }; +static struct unwind_user_frame compat_fp_frame = { + ARCH_INIT_USER_COMPAT_FP_FRAME +}; + static inline bool fp_state(struct unwind_user_state *state) { return IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP) && state->type == UNWIND_USER_TYPE_FP; } +static inline bool compat_state(struct unwind_user_state *state) +{ + return IS_ENABLED(CONFIG_HAVE_UNWIND_USER_COMPAT_FP) && + state->type == UNWIND_USER_TYPE_COMPAT_FP; +} + +#define UNWIND_GET_USER_LONG(to, from, state) \ +({ \ + int __ret; \ + if (compat_state(state)) \ + __ret = get_user(to, (u32 __user *)(from)); \ + else \ + __ret = get_user(to, (unsigned long __user *)(from)); \ + __ret; \ +}) + int unwind_user_next(struct unwind_user_state *state) { struct unwind_user_frame *frame; @@ -26,7 +46,9 @@ int unwind_user_next(struct unwind_user_state *state) if (state->done) return -EINVAL; - if (fp_state(state)) + if (compat_state(state)) + frame = &compat_fp_frame; + else if (fp_state(state)) frame = &fp_frame; else goto the_end; @@ -37,10 +59,10 @@ int unwind_user_next(struct unwind_user_state *state) if (cfa <= state->sp) goto the_end; - if (get_user(ra, (unsigned long *)(cfa + frame->ra_off))) + if (UNWIND_GET_USER_LONG(ra, cfa + frame->ra_off, state)) goto the_end; - if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off))) + if (frame->fp_off && UNWIND_GET_USER_LONG(fp, cfa + frame->fp_off, state)) goto the_end; state->ip = ra; @@ -48,6 +70,8 @@ int unwind_user_next(struct unwind_user_state *state) if (frame->fp_off) state->fp = fp; + arch_unwind_user_next(state); + return 0; the_end: @@ -66,7 +90,9 @@ int unwind_user_start(struct unwind_user_state *state) return -EINVAL; } - if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP)) + if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_COMPAT_FP) && in_compat_mode(regs)) + state->type = UNWIND_USER_TYPE_COMPAT_FP; + else if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP)) state->type = UNWIND_USER_TYPE_FP; else state->type = UNWIND_USER_TYPE_NONE; @@ -75,6 +101,8 @@ 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
