Mercurial > illumos > git > illumos-joyent
changeset 25231:d8949b8d8933
12747 sigsetjmp should allow for 8 byte aligned buffer on amd64
Reviewed by: Robert Mustacchi <rm@fingolfin.org>
Reviewed by: Joshua M. Clulow <josh@sysmgr.org>
Approved by: Joshua M. Clulow <josh@sysmgr.org>
| author | Vitaliy Gusev <gusev.vitaliy@gmail.com> |
|---|---|
| date | Mon, 20 Jul 2020 13:58:21 -0700 |
| parents | 8f171bd0ccda |
| children | 1e97e55a86d8 |
| files | usr/src/lib/libc/amd64/gen/siglongjmp.c usr/src/lib/libc/amd64/threads/asm_subr.s usr/src/lib/libc/amd64/threads/machdep.c usr/src/lib/libc/inc/sigjmp_struct.h |
| diffstat | 4 files changed, 26 insertions(+), 7 deletions(-) [+] |
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--- a/usr/src/lib/libc/amd64/gen/siglongjmp.c Mon Apr 13 10:15:27 2020 +0300 +++ b/usr/src/lib/libc/amd64/gen/siglongjmp.c Mon Jul 20 13:58:21 2020 -0700 @@ -29,6 +29,7 @@ #include <sys/ucontext.h> #include <setjmp.h> #include <ucontext.h> +#include "sigjmp_struct.h" #include "libc.h" #pragma weak _siglongjmp = siglongjmp @@ -36,8 +37,7 @@ void siglongjmp(sigjmp_buf env, int val) { - /* LINTED alignment */ - ucontext_t *ucp = (ucontext_t *)env; + ucontext_t *ucp = SIGJMP2UCONTEXT(env); if (val) ucp->uc_mcontext.gregs[REG_R0] = val;
--- a/usr/src/lib/libc/amd64/threads/asm_subr.s Mon Apr 13 10:15:27 2020 +0300 +++ b/usr/src/lib/libc/amd64/threads/asm_subr.s Mon Jul 20 13:58:21 2020 -0700 @@ -104,7 +104,11 @@ #undef sigsetjmp -#if SIZEOF_SIGJMP_BUF < SIZEOF_UCONTEXT_T +/* + * Ensure that a "ucontext_t" will fit within a "sigjmp_buf", including the + * extra 8 bytes we may need for correct alignment on AMD64. + */ +#if SIZEOF_SIGJMP_BUF - _LONG_ALIGNMENT < SIZEOF_UCONTEXT_T #error "sigjmp_buf is too small to contain a ucontext_t" @@ -171,4 +175,4 @@ SET_SIZE(sigsetjmp) SET_SIZE(_sigsetjmp) -#endif /* SIZEOF_SIGJMP_BUF < SIZEOF_UCONTEXT_T */ +#endif /* SIZEOF_SIGJMP_BUF - _LONG_ALIGNMENT < SIZEOF_UCONTEXT_T */
--- a/usr/src/lib/libc/amd64/threads/machdep.c Mon Apr 13 10:15:27 2020 +0300 +++ b/usr/src/lib/libc/amd64/threads/machdep.c Mon Jul 20 13:58:21 2020 -0700 @@ -28,6 +28,7 @@ #include <procfs.h> #include <ucontext.h> #include <setjmp.h> +#include "sigjmp_struct.h" extern int getlwpstatus(thread_t, lwpstatus_t *); extern int putlwpregs(thread_t, prgregset_t); @@ -66,7 +67,7 @@ int setup_context(ucontext_t *ucp, void *(*func)(ulwp_t *), - ulwp_t *ulwp, caddr_t stk, size_t stksize) + ulwp_t *ulwp, caddr_t stk, size_t stksize) { uint64_t *stack; @@ -172,8 +173,7 @@ int __csigsetjmp(sigjmp_buf env, int savemask, gregset_t rs) { - /* LINTED alignment */ - ucontext_t *ucp = (ucontext_t *)env; + ucontext_t *ucp = SIGJMP2UCONTEXT(env); ulwp_t *self = curthread; ucp->uc_link = self->ul_siglink;
--- a/usr/src/lib/libc/inc/sigjmp_struct.h Mon Apr 13 10:15:27 2020 +0300 +++ b/usr/src/lib/libc/inc/sigjmp_struct.h Mon Jul 20 13:58:21 2020 -0700 @@ -32,6 +32,7 @@ #include <sys/types.h> #include <sys/stack.h> +#include <sys/sysmacros.h> #include <ucontext.h> #include <setjmp.h> @@ -73,6 +74,20 @@ #endif /* __sparc */ +#if defined(__amd64) +/* + * The "sigjmp_buf" type is an array of long and thus can have 8-byte alignment + * on AMD64 systems. The "ucontext_t" type has a stricter 16-byte alignment + * requirement, so we must round the pointer up when casting. + * + * This is not required on other architectures: + * - SPARC does not store the ucontext_t in the sigjmp_buf + * - i386 only requires 4-byte alignment for ucontext_t + */ +#define SIGJMP2UCONTEXT(x) \ + ((ucontext_t *)P2ROUNDUP((uintptr_t)(x), sizeof (upad128_t))) +#endif + #ifdef __cplusplus } #endif