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x86-64: Allocate state buffer space for RDI, RSI and RBX

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_dl_tlsdesc_dynamic preserves RDI, RSI and RBX before realigning stack.
After realigning stack, it saves RCX, RDX, R8, R9, R10 and R11.  Define
TLSDESC_CALL_REGISTER_SAVE_AREA to allocate space for RDI, RSI and RBX
to avoid clobbering saved RDI, RSI and RBX values on stack by xsave to
STATE_SAVE_OFFSET(%rsp).

   +==================+<- stack frame start aligned at 8 or 16 bytes
   |                  |<- RDI saved in the red zone
   |                  |<- RSI saved in the red zone
   |                  |<- RBX saved in the red zone
   |                  |<- paddings for stack realignment of 64 bytes
   |------------------|<- xsave buffer end aligned at 64 bytes
   |                  |<-
   |                  |<-
   |                  |<-
   |------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp)
   |                  |<- 8-byte padding for 64-byte alignment
   |                  |<- 8-byte padding for 64-byte alignment
   |                  |<- R11
   |                  |<- R10
   |                  |<- R9
   |                  |<- R8
   |                  |<- RDX
   |                  |<- RCX
   +==================+<- RSP aligned at 64 bytes

Define TLSDESC_CALL_REGISTER_SAVE_AREA, the total register save area size
for all integer registers by adding 24 to STATE_SAVE_OFFSET since RDI, RSI
and RBX are saved onto stack without adjusting stack pointer first, using
the red-zone.  This fixes BZ #31501.
Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
This commit is contained in:
H.J. Lu
2024-03-18 06:40:16 -07:00
parent f44f3aed31
commit 717ebfa85c
3 changed files with 146 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
sysdeps/x86/cpu-features.c
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@ -311,7 +311,7 @@ update_active (struct cpu_features *cpu_features)
/* NB: On AMX capable processors, ebx always includes AMX
states. */
unsigned int xsave_state_full_size
= ALIGN_UP (ebx + STATE_SAVE_OFFSET, 64);
= ALIGN_UP (ebx + TLSDESC_CALL_REGISTER_SAVE_AREA, 64);
cpu_features->xsave_state_size
= xsave_state_full_size;
@ -401,8 +401,10 @@ update_active (struct cpu_features *cpu_features)
unsigned int amx_size
= (xstate_amx_comp_offsets[31]
+ xstate_amx_comp_sizes[31]);
amx_size = ALIGN_UP (amx_size + STATE_SAVE_OFFSET,
64);
amx_size
= ALIGN_UP ((amx_size
+ TLSDESC_CALL_REGISTER_SAVE_AREA),
64);
/* Set xsave_state_full_size to the compact AMX
state size for XSAVEC. NB: xsave_state_full_size
is only used in _dl_tlsdesc_dynamic_xsave and
@ -410,7 +412,8 @@ update_active (struct cpu_features *cpu_features)
cpu_features->xsave_state_full_size = amx_size;
#endif
cpu_features->xsave_state_size
= ALIGN_UP (size + STATE_SAVE_OFFSET, 64);
= ALIGN_UP (size + TLSDESC_CALL_REGISTER_SAVE_AREA,
64);
CPU_FEATURE_SET (cpu_features, XSAVEC);
}
}