Merge branch 'linus' into x86/asm, before applying dependent patch

[cascardo/linux.git] / arch / x86 / kernel / entry_64.S

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 02c2eff..7423e3e 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -419,26 +419,27 @@ syscall_return:
         * a completely clean 64-bit userspace context.
         */
        movq RCX(%rsp),%rcx
-       cmpq %rcx,RIP(%rsp)             /* RCX == RIP */
+       movq RIP(%rsp),%r11
+       cmpq %rcx,%r11                  /* RCX == RIP */
        jne opportunistic_sysret_failed
 
        /*
         * On Intel CPUs, SYSRET with non-canonical RCX/RIP will #GP
         * in kernel space.  This essentially lets the user take over
-        * the kernel, since userspace controls RSP.  It's not worth
-        * testing for canonicalness exactly -- this check detects any
-        * of the 17 high bits set, which is true for non-canonical
-        * or kernel addresses.  (This will pessimize vsyscall=native.
-        * Big deal.)
+        * the kernel, since userspace controls RSP.
         *
-        * If virtual addresses ever become wider, this will need
+        * If width of "canonical tail" ever becomes variable, this will need
         * to be updated to remain correct on both old and new CPUs.
         */
        .ifne __VIRTUAL_MASK_SHIFT - 47
        .error "virtual address width changed -- SYSRET checks need update"
        .endif
-       shr $__VIRTUAL_MASK_SHIFT, %rcx
-       jnz opportunistic_sysret_failed
+       /* Change top 16 bits to be the sign-extension of 47th bit */
+       shl     $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
+       sar     $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx
+       /* If this changed %rcx, it was not canonical */
+       cmpq    %rcx, %r11
+       jne     opportunistic_sysret_failed
 
        cmpq $__USER_CS,CS(%rsp)        /* CS must match SYSRET */
        jne opportunistic_sysret_failed
@@ -475,8 +476,8 @@ syscall_return:
         */
 syscall_return_via_sysret:
        CFI_REMEMBER_STATE
-       /* r11 is already restored (see code above) */
-       RESTORE_C_REGS_EXCEPT_R11
+       /* rcx and r11 are already restored (see code above) */
+       RESTORE_C_REGS_EXCEPT_RCX_R11
        movq RSP(%rsp),%rsp
        USERGS_SYSRET64
        CFI_RESTORE_STATE
@@ -533,40 +534,27 @@ GLOBAL(stub_execveat)
        CFI_ENDPROC
 END(stub_execveat)
 
-#ifdef CONFIG_X86_X32_ABI
+#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
        .align  8
 GLOBAL(stub_x32_execve)
+GLOBAL(stub32_execve)
        CFI_STARTPROC
        DEFAULT_FRAME 0, 8
        call    compat_sys_execve
        jmp     return_from_execve
        CFI_ENDPROC
+END(stub32_execve)
 END(stub_x32_execve)
        .align  8
 GLOBAL(stub_x32_execveat)
-       CFI_STARTPROC
-       DEFAULT_FRAME 0, 8
-       call    compat_sys_execveat
-       jmp     return_from_execve
-       CFI_ENDPROC
-END(stub_x32_execveat)
-#endif
-
-#ifdef CONFIG_IA32_EMULATION
-       .align  8
-GLOBAL(stub32_execve)
-       CFI_STARTPROC
-       call    compat_sys_execve
-       jmp     return_from_execve
-       CFI_ENDPROC
-END(stub32_execve)
-       .align  8
 GLOBAL(stub32_execveat)
        CFI_STARTPROC
+       DEFAULT_FRAME 0, 8
        call    compat_sys_execveat
        jmp     return_from_execve
        CFI_ENDPROC
 END(stub32_execveat)
+END(stub_x32_execveat)
 #endif
 
 /*
@@ -622,7 +610,7 @@ ENTRY(ret_from_fork)
 
        RESTORE_EXTRA_REGS
 
-       testl $3,CS(%rsp)                       # from kernel_thread?
+       testb   $3, CS(%rsp)                    # from kernel_thread?
 
        /*
         * By the time we get here, we have no idea whether our pt_regs,
@@ -686,8 +674,8 @@ END(irq_entries_start)
 
        leaq -RBP(%rsp),%rdi    /* arg1 for \func (pointer to pt_regs) */
 
-       testl $3, CS-RBP(%rsp)
-       je 1f
+       testb   $3, CS-RBP(%rsp)
+       jz      1f
        SWAPGS
 1:
        /*
@@ -741,8 +729,8 @@ ret_from_intr:
        CFI_DEF_CFA_REGISTER    rsp
        CFI_ADJUST_CFA_OFFSET   RBP
 
-       testl $3,CS(%rsp)
-       je retint_kernel
+       testb   $3, CS(%rsp)
+       jz      retint_kernel
        /* Interrupt came from user space */
 
        GET_THREAD_INFO(%rcx)
@@ -989,7 +977,7 @@ ENTRY(\sym)
        .if \paranoid
        .if \paranoid == 1
        CFI_REMEMBER_STATE
-       testl $3, CS(%rsp)              /* If coming from userspace, switch */
+       testb   $3, CS(%rsp)            /* If coming from userspace, switch */
        jnz 1f                          /* stacks. */
        .endif
        call paranoid_entry
@@ -1330,8 +1318,8 @@ ENTRY(error_entry)
        SAVE_C_REGS 8
        SAVE_EXTRA_REGS 8
        xorl %ebx,%ebx
-       testl $3,CS+8(%rsp)
-       je error_kernelspace
+       testb   $3, CS+8(%rsp)
+       jz      error_kernelspace
 error_swapgs:
        SWAPGS
 error_sti:
@@ -1382,7 +1370,7 @@ ENTRY(error_exit)
        TRACE_IRQS_OFF
        GET_THREAD_INFO(%rcx)
        testl %eax,%eax
-       jne retint_kernel
+       jnz retint_kernel
        LOCKDEP_SYS_EXIT_IRQ
        movl TI_flags(%rcx),%edx
        movl $_TIF_WORK_MASK,%edi
@@ -1627,7 +1615,6 @@ end_repeat_nmi:
        je 1f
        movq %r12, %cr2
 1:
-       
        testl %ebx,%ebx                         /* swapgs needed? */
        jnz nmi_restore
 nmi_swapgs: