summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/entry_64.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
-rw-r--r--arch/x86/kernel/entry_64.S74
1 files changed, 25 insertions, 49 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 44531acd9a81..cdc790c78f32 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -554,7 +554,7 @@ ENTRY(ret_from_fork)
RESTORE_REST
testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
- jz retint_restore_args
+ jz 1f
testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
jnz int_ret_from_sys_call
@@ -562,6 +562,16 @@ ENTRY(ret_from_fork)
RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
jmp ret_from_sys_call # go to the SYSRET fastpath
+1:
+ subq $REST_SKIP, %rsp # move the stack pointer back
+ CFI_ADJUST_CFA_OFFSET REST_SKIP
+ movq %rbp, %rdi
+ call *%rbx
+ # exit
+ mov %eax, %edi
+ call do_exit
+ ud2 # padding for call trace
+
CFI_ENDPROC
END(ret_from_fork)
@@ -862,7 +872,6 @@ ENTRY(stub_execve)
PARTIAL_FRAME 0
SAVE_REST
FIXUP_TOP_OF_STACK %r11
- movq %rsp, %rcx
call sys_execve
RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
@@ -912,8 +921,7 @@ ENTRY(stub_x32_execve)
PARTIAL_FRAME 0
SAVE_REST
FIXUP_TOP_OF_STACK %r11
- movq %rsp, %rcx
- call sys32_execve
+ call compat_sys_execve
RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
RESTORE_REST
@@ -1318,51 +1326,19 @@ bad_gs:
jmp 2b
.previous
-ENTRY(kernel_thread_helper)
- pushq $0 # fake return address
- CFI_STARTPROC
- /*
- * Here we are in the child and the registers are set as they were
- * at kernel_thread() invocation in the parent.
- */
- call *%rsi
- # exit
- mov %eax, %edi
- call do_exit
- ud2 # padding for call trace
- CFI_ENDPROC
-END(kernel_thread_helper)
-
-/*
- * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
- *
- * C extern interface:
- * extern long execve(const char *name, char **argv, char **envp)
- *
- * asm input arguments:
- * rdi: name, rsi: argv, rdx: envp
- *
- * We want to fallback into:
- * extern long sys_execve(const char *name, char **argv,char **envp, struct pt_regs *regs)
- *
- * do_sys_execve asm fallback arguments:
- * rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
- */
-ENTRY(kernel_execve)
- CFI_STARTPROC
- FAKE_STACK_FRAME $0
- SAVE_ALL
- movq %rsp,%rcx
- call sys_execve
- movq %rax, RAX(%rsp)
- RESTORE_REST
- testq %rax,%rax
- je int_ret_from_sys_call
- RESTORE_ARGS
- UNFAKE_STACK_FRAME
- ret
- CFI_ENDPROC
-END(kernel_execve)
+ENTRY(ret_from_kernel_execve)
+ movq %rdi, %rsp
+ movl $0, RAX(%rsp)
+ // RESTORE_REST
+ movq 0*8(%rsp), %r15
+ movq 1*8(%rsp), %r14
+ movq 2*8(%rsp), %r13
+ movq 3*8(%rsp), %r12
+ movq 4*8(%rsp), %rbp
+ movq 5*8(%rsp), %rbx
+ addq $(6*8), %rsp
+ jmp int_ret_from_sys_call
+END(ret_from_kernel_execve)
/* Call softirq on interrupt stack. Interrupts are off. */
ENTRY(call_softirq)