git: ba279bcd6d75 - main - linux(4): Cleanup signal trampolines
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Date: Sun, 15 May 2022 18:12:23 UTC
The branch main has been updated by dchagin:
URL: https://cgit.FreeBSD.org/src/commit/?id=ba279bcd6d75aa236bcb9ccf11aeb6f51a2f8514
commit ba279bcd6d75aa236bcb9ccf11aeb6f51a2f8514
Author: Dmitry Chagin <dchagin@FreeBSD.org>
AuthorDate: 2022-05-15 18:00:05 +0000
Commit: Dmitry Chagin <dchagin@FreeBSD.org>
CommitDate: 2022-05-15 18:00:05 +0000
linux(4): Cleanup signal trampolines
This is the first stage of a signal trampolines refactoring.
From trampolines retired emulation of the 'call' instruction, which is
replaced by direct call of a signal handler. The signal handler address
is in the register.
The previous trampoline implemenatation used semi-Linux-way to call
a signal handler via the 'jmp' instruction. Wherefore the trampoline
emulated a 'call' instruction to into the stack the return address for
signal handler's 'ret' instruction. Wherefore handmade DWARD annotations
was used.
While here rephrased and removed excessive comments.
MFC after: 2 weeks
---
sys/amd64/linux/linux.h | 1 -
sys/amd64/linux/linux_genassym.c | 1 -
sys/amd64/linux/linux_locore.asm | 19 +++++--------------
sys/amd64/linux/linux_sysvec.c | 2 +-
sys/amd64/linux32/linux.h | 4 ----
sys/amd64/linux32/linux32_genassym.c | 2 --
sys/amd64/linux32/linux32_locore.asm | 34 +++++++++-------------------------
sys/amd64/linux32/linux32_sysvec.c | 4 ++--
sys/i386/linux/linux.h | 4 ----
sys/i386/linux/linux_genassym.c | 2 --
sys/i386/linux/linux_locore.asm | 32 ++++++++------------------------
sys/i386/linux/linux_sysvec.c | 4 ++--
12 files changed, 27 insertions(+), 82 deletions(-)
diff --git a/sys/amd64/linux/linux.h b/sys/amd64/linux/linux.h
index 920ca98ce01b..08cf3d4b6bbd 100644
--- a/sys/amd64/linux/linux.h
+++ b/sys/amd64/linux/linux.h
@@ -314,7 +314,6 @@ typedef struct l_siginfo {
struct l_rt_sigframe {
struct l_ucontext sf_sc;
struct l_siginfo sf_si;
- l_handler_t sf_handler;
};
/*
diff --git a/sys/amd64/linux/linux_genassym.c b/sys/amd64/linux/linux_genassym.c
index 0edb6a043531..73febbe6ef40 100644
--- a/sys/amd64/linux/linux_genassym.c
+++ b/sys/amd64/linux/linux_genassym.c
@@ -8,7 +8,6 @@ __FBSDID("$FreeBSD$");
#include <amd64/linux/linux.h>
#include <compat/linux/linux_mib.h>
-ASSYM(LINUX_RT_SIGF_HANDLER, offsetof(struct l_rt_sigframe, sf_handler));
ASSYM(LINUX_RT_SIGF_UC, offsetof(struct l_rt_sigframe, sf_sc));
ASSYM(LINUX_RT_SIGF_SC, offsetof(struct l_ucontext, uc_mcontext));
ASSYM(LINUX_VERSION_CODE, LINUX_VERSION_CODE);
diff --git a/sys/amd64/linux/linux_locore.asm b/sys/amd64/linux/linux_locore.asm
index dd482cb87cc8..8b6833d7352f 100644
--- a/sys/amd64/linux/linux_locore.asm
+++ b/sys/amd64/linux/linux_locore.asm
@@ -11,23 +11,14 @@
linux_platform:
.asciz "x86_64"
-
.text
-/*
- * To avoid excess stack frame the signal trampoline code emulates
- * the 'call' instruction.
- */
+
ENTRY(linux_rt_sigcode)
- movq %rsp, %rbx /* preserve sigframe */
- call .getip
-.getip:
- popq %rax
- add $.startrtsigcode-.getip, %rax /* ret address */
- pushq %rax
- jmp *LINUX_RT_SIGF_HANDLER(%rbx)
+ movq %rsp, %rbx /* rt_sigframe for rt_sigreturn */
+ call *%rcx /* call signal handler */
.startrtsigcode:
- movq $LINUX_SYS_linux_rt_sigreturn,%rax /* linux_rt_sigreturn() */
- syscall /* enter kernel with args */
+ movq $LINUX_SYS_linux_rt_sigreturn, %rax
+ syscall
hlt
.endrtsigcode:
0: jmp 0b
diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
index 1ea274da8935..ea91dcae5d49 100644
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -686,10 +686,10 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
regs->tf_rax = 0;
regs->tf_rsi = (register_t)&sfp->sf_si; /* arg 2 in %rsi */
regs->tf_rdx = (register_t)&sfp->sf_sc; /* arg 3 in %rdx */
+ regs->tf_rcx = (register_t)catcher;
/* Fill in POSIX parts. */
siginfo_to_lsiginfo(&ksi->ksi_info, &sf.sf_si, sig);
- sf.sf_handler = catcher;
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(p);
diff --git a/sys/amd64/linux32/linux.h b/sys/amd64/linux32/linux.h
index 1273ff485dd9..ba7aeac517e1 100644
--- a/sys/amd64/linux32/linux.h
+++ b/sys/amd64/linux32/linux.h
@@ -429,15 +429,12 @@ struct l_fpstate {
/*
* We make the stack look like Linux expects it when calling a signal
* handler, but use the BSD way of calling the handler and sigreturn().
- * This means that we need to pass the pointer to the handler too.
- * It is appended to the frame to not interfere with the rest of it.
*/
struct l_sigframe {
l_int sf_sig;
struct l_sigcontext sf_sc;
struct l_fpstate sf_fpstate;
l_uint sf_extramask[1];
- l_handler_t sf_handler;
};
struct l_rt_sigframe {
@@ -446,7 +443,6 @@ struct l_rt_sigframe {
l_uintptr_t sf_ucontext;
l_siginfo_t sf_si;
struct l_ucontext sf_sc;
- l_handler_t sf_handler;
} __packed;
/*
diff --git a/sys/amd64/linux32/linux32_genassym.c b/sys/amd64/linux32/linux32_genassym.c
index bc94139c226d..ca618c01ffab 100644
--- a/sys/amd64/linux32/linux32_genassym.c
+++ b/sys/amd64/linux32/linux32_genassym.c
@@ -9,9 +9,7 @@ __FBSDID("$FreeBSD$");
#include <amd64/linux32/linux.h>
#include <compat/linux/linux_mib.h>
-ASSYM(LINUX_SIGF_HANDLER, offsetof(struct l_sigframe, sf_handler));
ASSYM(LINUX_SIGF_SC, offsetof(struct l_sigframe, sf_sc));
-ASSYM(LINUX_RT_SIGF_HANDLER, offsetof(struct l_rt_sigframe, sf_handler));
ASSYM(LINUX_RT_SIGF_UC, offsetof(struct l_rt_sigframe, sf_sc));
ASSYM(LINUX_RT_SIGF_SC, offsetof(struct l_ucontext, uc_mcontext));
ASSYM(LINUX_VERSION_CODE, LINUX_VERSION_CODE);
diff --git a/sys/amd64/linux32/linux32_locore.asm b/sys/amd64/linux32/linux32_locore.asm
index f96b3e730f9f..e0409969ee3b 100644
--- a/sys/amd64/linux32/linux32_locore.asm
+++ b/sys/amd64/linux32/linux32_locore.asm
@@ -14,38 +14,22 @@ linux_platform:
.text
.code32
-/*
- * To avoid excess stack frame the signal trampoline code emulates
- * the 'call' instruction.
- */
ENTRY(__kernel_sigreturn)
- movl %esp, %ebx /* preserve sigframe */
- call .getip0
-.getip0:
- popl %eax
- add $.startsigcode-.getip0, %eax /* ret address */
- push %eax
- jmp *LINUX_SIGF_HANDLER(%ebx)
+ movl %esp, %ebx /* sigframe for sigreturn */
+ call *%edi /* call signal handler */
.startsigcode:
- popl %eax
- movl $LINUX32_SYS_linux_sigreturn,%eax /* linux_sigreturn() */
- int $0x80 /* enter kernel with args */
+ popl %eax /* gcc unwind code need this */
+ movl $LINUX32_SYS_linux_sigreturn, %eax
+ int $0x80
.endsigcode:
0: jmp 0b
ENTRY(__kernel_rt_sigreturn)
- leal LINUX_RT_SIGF_UC(%esp),%ebx /* linux ucp */
- leal LINUX_RT_SIGF_SC(%ebx),%ecx /* linux sigcontext */
- movl %esp, %edi
- call .getip1
-.getip1:
- popl %eax
- add $.startrtsigcode-.getip1, %eax /* ret address */
- push %eax
- jmp *LINUX_RT_SIGF_HANDLER(%edi)
+ leal LINUX_RT_SIGF_UC(%esp), %ebx /* linux ucontext for rt_sigreturn */
+ call *%edi /* call signal handler */
.startrtsigcode:
- movl $LINUX32_SYS_linux_rt_sigreturn,%eax /* linux_rt_sigreturn() */
- int $0x80 /* enter kernel with args */
+ movl $LINUX32_SYS_linux_rt_sigreturn, %eax
+ int $0x80
.endrtsigcode:
0: jmp 0b
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index ed430c8e579a..b2d0f2401bf9 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -314,7 +314,6 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
bzero(&frame, sizeof(frame));
- frame.sf_handler = PTROUT(catcher);
frame.sf_sig = sig;
frame.sf_siginfo = PTROUT(&fp->sf_si);
frame.sf_ucontext = PTROUT(&fp->sf_sc);
@@ -367,6 +366,7 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
/* Build context to run handler in. */
regs->tf_rsp = PTROUT(fp);
regs->tf_rip = __kernel_rt_sigreturn;
+ regs->tf_rdi = PTROUT(catcher);
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;
@@ -431,7 +431,6 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
bzero(&frame, sizeof(frame));
- frame.sf_handler = PTROUT(catcher);
frame.sf_sig = sig;
bsd_to_linux_sigset(mask, &lmask);
@@ -473,6 +472,7 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
/* Build context to run handler in. */
regs->tf_rsp = PTROUT(fp);
regs->tf_rip = __kernel_sigreturn;
+ regs->tf_rdi = PTROUT(catcher);
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;
diff --git a/sys/i386/linux/linux.h b/sys/i386/linux/linux.h
index 7fed468239a8..c26294ddc178 100644
--- a/sys/i386/linux/linux.h
+++ b/sys/i386/linux/linux.h
@@ -404,15 +404,12 @@ struct l_fpstate {
/*
* We make the stack look like Linux expects it when calling a signal
* handler, but use the BSD way of calling the handler and sigreturn().
- * This means that we need to pass the pointer to the handler too.
- * It is appended to the frame to not interfere with the rest of it.
*/
struct l_sigframe {
l_int sf_sig;
struct l_sigcontext sf_sc;
struct l_fpstate sf_fpstate;
l_uint sf_extramask[LINUX_NSIG_WORDS-1];
- l_handler_t sf_handler;
};
struct l_rt_sigframe {
@@ -421,7 +418,6 @@ struct l_rt_sigframe {
struct l_ucontext *sf_ucontext;
l_siginfo_t sf_si;
struct l_ucontext sf_sc;
- l_handler_t sf_handler;
};
extern struct sysentvec linux_sysvec;
diff --git a/sys/i386/linux/linux_genassym.c b/sys/i386/linux/linux_genassym.c
index 9735110b0472..08aa0979d793 100644
--- a/sys/i386/linux/linux_genassym.c
+++ b/sys/i386/linux/linux_genassym.c
@@ -8,11 +8,9 @@ __FBSDID("$FreeBSD$");
#include <i386/linux/linux.h>
#include <compat/linux/linux_mib.h>
-ASSYM(LINUX_SIGF_HANDLER, offsetof(struct l_sigframe, sf_handler));
ASSYM(LINUX_SIGF_SC, offsetof(struct l_sigframe, sf_sc));
ASSYM(LINUX_SC_GS, offsetof(struct l_sigcontext, sc_gs));
ASSYM(LINUX_SC_EFLAGS, offsetof(struct l_sigcontext, sc_eflags));
-ASSYM(LINUX_RT_SIGF_HANDLER, offsetof(struct l_rt_sigframe, sf_handler));
ASSYM(LINUX_RT_SIGF_UC, offsetof(struct l_rt_sigframe, sf_sc));
ASSYM(LINUX_RT_SIGF_SC, offsetof(struct l_ucontext, uc_mcontext));
ASSYM(LINUX_SC_ESP, offsetof(struct l_sigcontext, sc_esp));
diff --git a/sys/i386/linux/linux_locore.asm b/sys/i386/linux/linux_locore.asm
index 4c5246bd5725..3459fb5a56de 100644
--- a/sys/i386/linux/linux_locore.asm
+++ b/sys/i386/linux/linux_locore.asm
@@ -15,38 +15,22 @@ linux_platform:
.text
-/*
- * To avoid excess stack frame the signal trampoline code emulates
- * the 'call' instruction.
- */
ENTRY(__kernel_sigreturn)
- movl %esp, %ebx /* preserve sigframe */
- call .getip0
-.getip0:
- popl %eax
- add $.startsigcode-.getip0, %eax /* ret address */
- push %eax
- jmp *LINUX_SIGF_HANDLER(%ebx)
+ movl %esp, %ebx /* sigframe for sigreturn */
+ call *%edi /* call signal handler */
.startsigcode:
popl %eax /* gcc unwind code need this */
- movl $LINUX_SYS_linux_sigreturn,%eax /* linux_sigreturn() */
- int $0x80 /* enter kernel with args */
+ movl $LINUX_SYS_linux_sigreturn, %eax
+ int $0x80
.endsigcode:
0: jmp 0b
ENTRY(__kernel_rt_sigreturn)
- leal LINUX_RT_SIGF_UC(%esp),%ebx /* linux ucp */
- leal LINUX_RT_SIGF_SC(%ebx),%ecx /* linux sigcontext */
- movl %esp, %edi
- call .getip1
-.getip1:
- popl %eax
- add $.startrtsigcode-.getip1, %eax /* ret address */
- push %eax
- jmp *LINUX_RT_SIGF_HANDLER(%edi)
+ leal LINUX_RT_SIGF_UC(%esp), %ebx /* linux ucontext for rt_sigreturn */
+ call *%edi /* call signal handler */
.startrtsigcode:
- movl $LINUX_SYS_linux_rt_sigreturn,%eax /* linux_rt_sigreturn() */
- int $0x80 /* enter kernel with args */
+ movl $LINUX_SYS_linux_rt_sigreturn, %eax
+ int $0x80
.endrtsigcode:
0: jmp 0b
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index 9f0647f73c0c..d37250d7552f 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -422,7 +422,6 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
bzero(&frame, sizeof(frame));
- frame.sf_handler = catcher;
frame.sf_sig = sig;
frame.sf_siginfo = &fp->sf_si;
frame.sf_ucontext = &fp->sf_sc;
@@ -473,6 +472,7 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
/* Build context to run handler in. */
regs->tf_esp = (int)fp;
regs->tf_eip = __kernel_rt_sigreturn;
+ regs->tf_edi = catcher;
regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
@@ -532,7 +532,6 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
bzero(&frame, sizeof(frame));
- frame.sf_handler = catcher;
frame.sf_sig = sig;
bsd_to_linux_sigset(mask, &lmask);
@@ -574,6 +573,7 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
/* Build context to run handler in. */
regs->tf_esp = (int)fp;
regs->tf_eip = __kernel_sigreturn;
+ regs->tf_edi = catcher;
regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;