diff options
| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2022-11-22 15:39:04 -0500 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-12-27 12:52:10 +0100 |
| commit | 317c8194e6aeb8b3b573ad139fc2a0635856498e (patch) | |
| tree | 487894b9890601c50b9a966a3708c2922ae78ba8 | |
| parent | 4842dadfc66f627083ec46c4e9a426e805c765f3 (diff) | |
rseq: Introduce feature size and alignment ELF auxiliary vector entries
Export the rseq feature size supported by the kernel as well as the
required allocation alignment for the rseq per-thread area to user-space
through ELF auxiliary vector entries.
This is part of the extensible rseq ABI.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-3-mathieu.desnoyers@efficios.com
| -rw-r--r-- | fs/binfmt_elf.c | 5 | ||||
| -rw-r--r-- | include/uapi/linux/auxvec.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/rseq.h | 5 |
3 files changed, 12 insertions, 0 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index de63572a9404..0ba86f0b1477 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -46,6 +46,7 @@ #include <linux/cred.h> #include <linux/dax.h> #include <linux/uaccess.h> +#include <linux/rseq.h> #include <asm/param.h> #include <asm/page.h> @@ -288,6 +289,10 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, if (bprm->have_execfd) { NEW_AUX_ENT(AT_EXECFD, bprm->execfd); } +#ifdef CONFIG_RSEQ + NEW_AUX_ENT(AT_RSEQ_FEATURE_SIZE, offsetof(struct rseq, end)); + NEW_AUX_ENT(AT_RSEQ_ALIGN, __alignof__(struct rseq)); +#endif #undef NEW_AUX_ENT /* AT_NULL is zero; clear the rest too */ memset(elf_info, 0, (char *)mm->saved_auxv + diff --git a/include/uapi/linux/auxvec.h b/include/uapi/linux/auxvec.h index c7e502bf5a6f..6991c4b8ab18 100644 --- a/include/uapi/linux/auxvec.h +++ b/include/uapi/linux/auxvec.h @@ -30,6 +30,8 @@ * differ from AT_PLATFORM. */ #define AT_RANDOM 25 /* address of 16 random bytes */ #define AT_HWCAP2 26 /* extension of AT_HWCAP */ +#define AT_RSEQ_FEATURE_SIZE 27 /* rseq supported feature size */ +#define AT_RSEQ_ALIGN 28 /* rseq allocation alignment */ #define AT_EXECFN 31 /* filename of program */ diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index 77ee207623a9..05d3c4cdeb40 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -130,6 +130,11 @@ struct rseq { * this thread. */ __u32 flags; + + /* + * Flexible array member at end of structure, after last feature field. + */ + char end[]; } __attribute__((aligned(4 * sizeof(__u64)))); #endif /* _UAPI_LINUX_RSEQ_H */ |