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new 46c319d9489 arch/x64: Solve the sig_nest hang issue
46c319d9489 is described below
commit 46c319d9489b7effd69492df43034947d2a788ba
Author: liwenxiang1 <[email protected]>
AuthorDate: Sun Mar 16 22:24:31 2025 +0800
arch/x64: Solve the sig_nest hang issue
When an interrupt occurs, the hardware automatically pushes the current
RIP/RSP onto the interrupt stack. During the interrupt return, the iretq
instruction pops them back. The problem is that the RIP/RSP modified by the
signal is stored in the XCP context, whereas iretq operates on the interrupt
stack. As a result, the RIP/RSP modified by the signal does not take effect in
the iretq instruction, causing the task receiving the signal to fail to jump
correctly to the signal handler. Th [...]
Signed-off-by: liwenxiang1 <[email protected]>
---
arch/x86_64/include/intel64/irq.h | 8 ----
arch/x86_64/src/common/x86_64_hwdebug.c | 4 --
arch/x86_64/src/intel64/intel64_vectors.S | 72 -------------------------------
3 files changed, 84 deletions(-)
diff --git a/arch/x86_64/include/intel64/irq.h
b/arch/x86_64/include/intel64/irq.h
index 63f600dbaae..24fd088d29c 100644
--- a/arch/x86_64/include/intel64/irq.h
+++ b/arch/x86_64/include/intel64/irq.h
@@ -468,10 +468,6 @@
#define XMMAREA_REGS (26)
-/* Aux register used by implementation */
-
-#define REG_AUX (27 + XMMAREA_REG_OFFSET)
-
/* NOTE 2: This is not really state data. Rather, this is just a convenient
* way to pass parameters from the interrupt handler to C code.
*/
@@ -490,10 +486,6 @@
#define XCP_ALIGN_DOWN(a) ((a) & ~XCP_ALIGN_MASK)
#define XCP_ALIGN_UP(a) (((a) + XCP_ALIGN_MASK) & ~XCP_ALIGN_MASK)
-/* Aux register flags */
-
-#define REG_AUX_FULLCONTEXT (1 << 0) /* Force full context switch */
-
/****************************************************************************
* Public Types
****************************************************************************/
diff --git a/arch/x86_64/src/common/x86_64_hwdebug.c
b/arch/x86_64/src/common/x86_64_hwdebug.c
index d86440176b0..2b411b5dee2 100644
--- a/arch/x86_64/src/common/x86_64_hwdebug.c
+++ b/arch/x86_64/src/common/x86_64_hwdebug.c
@@ -234,10 +234,6 @@ static void x86_64_debug_step(bool enable)
{
regs[REG_RFLAGS] &= ~X86_64_RFLAGS_TF;
}
-
- /* Request full context switch so we update RFLAGS */
-
- regs[REG_AUX] |= REG_AUX_FULLCONTEXT;
}
/****************************************************************************
diff --git a/arch/x86_64/src/intel64/intel64_vectors.S
b/arch/x86_64/src/intel64/intel64_vectors.S
index 573f94a2041..823b636106e 100644
--- a/arch/x86_64/src/intel64/intel64_vectors.S
+++ b/arch/x86_64/src/intel64/intel64_vectors.S
@@ -828,80 +828,8 @@ irq_common:
/* The common return point for irq_handler */
-.Lreturn:
-
- /* Check if full context switch is required for signal handling */
-
- movq (8*REG_AUX)(%rax), %rcx
- cmp $(REG_AUX_FULLCONTEXT), %rcx
- je .Lfullswitch
-
- /* EAX may possibly hold a pointer to a different register save area on
- * return. Are we switching to a new context?
- */
-
- cmp %rax, %rdi
- je .Lnoswitch
-
-.Lfullswitch:
- /* Reset flag */
-
- movq $0x0, (8*REG_AUX)(%rdi)
-
- /* A context switch will be performed. RAX holds the address of the new
- * register save structure.
- *
- * Jump to x86_64_fullcontextrestore(). We perform a call here, but
that function
- * never returns. The address of the new register save block is the
argument
- * to the x86_64_fullcontextrestore().
- */
-
movq %rax, %rdi
call x86_64_fullcontextrestore
-
-.Lnoswitch:
-#ifndef CONFIG_ARCH_X86_64_HAVE_XSAVE
- fxrstorq (%rdi)
-#else
- movl $XSAVE_STATE_COMPONENTS, %eax
- xor %edx, %edx
- xrstor (%rdi)
-#endif
-
- movq (8*REG_FS)(%rdi), %rax
- mov %fs, %ax
- movq (8*REG_GS)(%rdi), %rax
- mov %gs, %ax
- movq (8*REG_ES)(%rdi), %rax
- mov %es, %ax
- movq (8*REG_DS)(%rdi), %rax
- mov %ds, %ax
-
- movq (8*REG_RAX)(%rdi), %rax
- movq (8*REG_RBX)(%rdi), %rbx
- movq (8*REG_RBP)(%rdi), %rbp
- movq (8*REG_R10)(%rdi), %r10
- movq (8*REG_R11)(%rdi), %r11
- movq (8*REG_R12)(%rdi), %r12
- movq (8*REG_R13)(%rdi), %r13
- movq (8*REG_R14)(%rdi), %r14
- movq (8*REG_R15)(%rdi), %r15
-
- movq (8*REG_R9)(%rdi), %r9
- movq (8*REG_R8)(%rdi), %r8
- movq (8*REG_RCX)(%rdi), %rcx
- movq (8*REG_RDX)(%rdi), %rdx
-
- /* Pop RDI and RSI pushed on interrupt entry */
-
- popq %rsi
- popq %rdi
-
- /* Cleans up the pushed error code */
-
- add $8, %rsp
-
- iretq /* Pops 5 things at once: RIP, CS, RFLAGS RSP and
SS */
.size irq_common, . - irq_common
.end
