From 1eeb207f870f746a863e5c59321d837d2d91c218 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko <dvlasenk@redhat.com> Date: Thu, 26 Feb 2015 14:40:33 -0800 Subject: [PATCH] x86/asm/entry/64: Move 'save_paranoid' and 'ret_from_fork' closer to their users For some odd reason, these two functions are at the very top of the file. "save_paranoid"'s caller is approximately in the middle of it, move it there. Move 'ret_from_fork' to be right after fork/exec helpers. This is a pure block move, nothing is changed in the function bodies. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/6446bbfe4094532623a5b83779b7015fec167a9d.1424989793.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/entry_64.S | 106 ++++++++++++++++++------------------- 1 file changed, 53 insertions(+), 53 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index e5cbfbbf94793..9e33d492ace39 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -202,59 +202,6 @@ ENDPROC(native_usergs_sysret64) CFI_REL_OFFSET r15, R15+\offset .endm -ENTRY(save_paranoid) - XCPT_FRAME 1 RDI+8 - cld - SAVE_C_REGS 8 - SAVE_EXTRA_REGS 8 - movl $1,%ebx - movl $MSR_GS_BASE,%ecx - rdmsr - testl %edx,%edx - js 1f /* negative -> in kernel */ - SWAPGS - xorl %ebx,%ebx -1: ret - CFI_ENDPROC -END(save_paranoid) - -/* - * A newly forked process directly context switches into this address. - * - * rdi: prev task we switched from - */ -ENTRY(ret_from_fork) - DEFAULT_FRAME - - LOCK ; btr $TIF_FORK,TI_flags(%r8) - - pushq_cfi $0x0002 - popfq_cfi # reset kernel eflags - - call schedule_tail # rdi: 'prev' task parameter - - GET_THREAD_INFO(%rcx) - - RESTORE_EXTRA_REGS - - testl $3,CS(%rsp) # from kernel_thread? - jz 1f - - testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET - jnz int_ret_from_sys_call - - RESTORE_TOP_OF_STACK %rdi - jmp ret_from_sys_call # go to the SYSRET fastpath - -1: - movq %rbp, %rdi - call *%rbx - movl $0, RAX(%rsp) - RESTORE_EXTRA_REGS - jmp int_ret_from_sys_call - CFI_ENDPROC -END(ret_from_fork) - /* * 64bit SYSCALL instruction entry. Up to 6 arguments in registers. * @@ -581,6 +528,43 @@ END(stub_x32_execveat) #endif +/* + * A newly forked process directly context switches into this address. + * + * rdi: prev task we switched from + */ +ENTRY(ret_from_fork) + DEFAULT_FRAME + + LOCK ; btr $TIF_FORK,TI_flags(%r8) + + pushq_cfi $0x0002 + popfq_cfi # reset kernel eflags + + call schedule_tail # rdi: 'prev' task parameter + + GET_THREAD_INFO(%rcx) + + RESTORE_EXTRA_REGS + + testl $3,CS(%rsp) # from kernel_thread? + jz 1f + + testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET + jnz int_ret_from_sys_call + + RESTORE_TOP_OF_STACK %rdi + jmp ret_from_sys_call # go to the SYSRET fastpath + +1: + movq %rbp, %rdi + call *%rbx + movl $0, RAX(%rsp) + RESTORE_EXTRA_REGS + jmp int_ret_from_sys_call + CFI_ENDPROC +END(ret_from_fork) + /* * Build the entry stubs and pointer table with some assembler magic. * We pack 7 stubs into a single 32-byte chunk, which will fit in a @@ -1273,6 +1257,22 @@ idtentry async_page_fault do_async_page_fault has_error_code=1 idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip) #endif +ENTRY(save_paranoid) + XCPT_FRAME 1 RDI+8 + cld + SAVE_C_REGS 8 + SAVE_EXTRA_REGS 8 + movl $1,%ebx + movl $MSR_GS_BASE,%ecx + rdmsr + testl %edx,%edx + js 1f /* negative -> in kernel */ + SWAPGS + xorl %ebx,%ebx +1: ret + CFI_ENDPROC +END(save_paranoid) + /* * "Paranoid" exit path from exception stack. This is invoked * only on return from non-NMI IST interrupts that came -- 2.30.2