From a30987291962ea81d6d261232c4ac39efa23ab41 Mon Sep 17 00:00:00 2001 Message-ID: In-Reply-To: <7f56d9ee24976d45babdc3856c85d47df2ae8a13.1752857321.git.sam@gentoo.org> References: <7f56d9ee24976d45babdc3856c85d47df2ae8a13.1752857321.git.sam@gentoo.org> From: Josh Poimboeuf Date: Wed, 16 Jul 2025 21:28:59 -0400 Subject: [PATCH 34/34] unwind_user/sframe: Add prctl() interface for registering .sframe sections The kernel doesn't have direct visibility to the ELF contents of shared libraries. Add some prctl() interfaces which allow glibc to tell the kernel where to find .sframe sections. [ This adds an interface for prctl() for testing loading of sframes for libraries. But this interface should really be a system call. This patch is for testing purposes only and should not be applied to mainline. ] Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- include/uapi/linux/prctl.h | 6 +++++- kernel/sys.c | 9 +++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 43dec6eed559a..c575cf7151b12 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -351,7 +351,7 @@ struct prctl_mm_map { * configuration. All bits may be locked via this call, including * undefined bits. */ -#define PR_LOCK_SHADOW_STACK_STATUS 76 +#define PR_LOCK_SHADOW_STACK_STATUS 76 /* * Controls the mode of timer_create() for CRIU restore operations. @@ -371,4 +371,8 @@ struct prctl_mm_map { # define PR_FUTEX_HASH_GET_SLOTS 2 # define PR_FUTEX_HASH_GET_IMMUTABLE 3 +/* SFRAME management */ +#define PR_ADD_SFRAME 79 +#define PR_REMOVE_SFRAME 80 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index adc0de0aa364a..cf788e66dc86c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -65,6 +65,7 @@ #include #include #include +#include #include @@ -2824,6 +2825,14 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_FUTEX_HASH: error = futex_hash_prctl(arg2, arg3, arg4); break; + case PR_ADD_SFRAME: + error = sframe_add_section(arg2, arg3, arg4, arg5); + break; + case PR_REMOVE_SFRAME: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = sframe_remove_section(arg2); + break; default: trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5); error = -EINVAL; -- 2.50.1