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| author | Sergey Bugaev <bugaevc@gmail.com> | 2023-05-17 22:14:28 +0300 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2023-05-17 22:52:39 +0200 |
| commit | 4a373ea7d677c69dc95903dbb542237ab1380eb5 (patch) | |
| tree | 27f0d9d478bf4fc513dbaaa0aa5f2a7afe9f15c8 /sysdeps/mach/x86 | |
| parent | 3f7b800d54eb67d9b97f6e0933275155fdf13c70 (diff) | |
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mach: Define MACHINE_THREAD_STATE_SETUP_CALL
The existing two macros, MACHINE_THREAD_STATE_SET_PC and
MACHINE_THREAD_STATE_SET_SP, can be used to set program counter and the
stack pointer registers in a machine-specific thread state structure.
Useful as it is, this may not be enough to set up the thread to make a
function call, because the machine-specific ABI may impose additional
requirements. In particular, x86_64 ABI requires that upon function
entry, the stack pointer is 8 less than 16-byte aligned (sp & 15 == 8).
To deal with this, introduce a new macro,
MACHINE_THREAD_STATE_SETUP_CALL (), which sets both stack and
instruction pointers, and also applies any machine-specific requirements
to make a valid function call. The default implementation simply
forwards to MACHINE_THREAD_STATE_SET_PC and MACHINE_THREAD_STATE_SET_SP,
but on x86_64 we additionally align the stack pointer.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230517191436.73636-3-bugaevc@gmail.com>
Diffstat (limited to 'sysdeps/mach/x86')
| -rw-r--r-- | sysdeps/mach/x86/thread_state.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/sysdeps/mach/x86/thread_state.h b/sysdeps/mach/x86/thread_state.h index 5be0bec150..8c419515f9 100644 --- a/sysdeps/mach/x86/thread_state.h +++ b/sysdeps/mach/x86/thread_state.h @@ -20,6 +20,7 @@ #define _MACH_X86_THREAD_STATE_H 1 #include <mach/machine/thread_status.h> +#include <libc-pointer-arith.h> /* This lets the kernel define segments for a new thread. */ #define MACHINE_NEW_THREAD_STATE_FLAVOR i386_THREAD_STATE @@ -54,6 +55,18 @@ struct machine_thread_all_state struct i386_float_state fpu; }; +#ifdef __x86_64__ +/* We're setting up the stack to perform a function call. On function entry, + the stack pointer must be 8 bytes less than 16-aligned. */ +#define PTR_ALIGN_DOWN_8_16(ptr) \ + ({ uintptr_t __ptr = PTR_ALIGN_DOWN (ptr, 8); \ + PTR_IS_ALIGNED (__ptr, 16) ? (__ptr - 8) : __ptr; }) + +#define MACHINE_THREAD_STATE_SETUP_CALL(ts, stack, size, func) \ + ((ts)->SP = PTR_ALIGN_DOWN_8_16 ((uintptr_t) (stack) + (size)), \ + (ts)->PC = (uintptr_t) func) +#endif + #include <sysdeps/mach/thread_state.h> #endif /* mach/x86/thread_state.h */ |