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[NTOS:KE/x64] Fix handling of non-volatiles in trap vs exception frame

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The registers that are saved/restored in the trap / exception frame need to be consistent between all entry/exit points as well as the functions that convert between trap/exception frame and context. The trap frame contains only the non-volatile registers and rbp, the rest is saved in the exception frame.
The previous code didn't save rbp in the syscall handler, which led to it being clobbered when exiting though KiServiceExit2 rather than returning back to the syscall exit path. Also KeContextToTrapFrame would use rbx, rsi and rdi from the trap frame, which wouldn't be saved there by the syscall handler.
This commit is contained in:
Timo Kreuzer 2022-12-15 21:55:16 +02:00
parent 83e741c643
commit 05456808e8
3 changed files with 6 additions and 21 deletions
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17
sdk/include/asm/trapamd64.inc
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@ -108,16 +108,6 @@ MACRO(EnterTrap, Flags)
lea rbp, [rsp]
.setframe rbp, 0
if (Flags AND TF_NONVOLATILES)
/* Save non-volatile registers */
mov [rbp + KTRAP_FRAME_Rbx], rbx
.savereg rbx, KTRAP_FRAME_Rbx
mov [rbp + KTRAP_FRAME_Rdi], rdi
.savereg rdi, KTRAP_FRAME_Rdi
mov [rbp + KTRAP_FRAME_Rsi], rsi
.savereg rsi, KTRAP_FRAME_Rsi
endif
.endprolog
if (Flags AND TF_VOLATILES)
@ -243,13 +233,6 @@ MACRO(ExitTrap, Flags)
kernel_mode_return:
if (Flags AND TF_NONVOLATILES)
/* Restore non-volatile registers */
mov rbx, [rbp + KTRAP_FRAME_Rbx]
mov rdi, [rbp + KTRAP_FRAME_Rdi]
mov rsi, [rbp + KTRAP_FRAME_Rsi]
endif
if (Flags AND TF_VOLATILES)
/* Restore volatile registers */
mov rax, [rbp + KTRAP_FRAME_Rax]