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Message-ID: <tip-1eeb207f870f746a863e5c59321d837d2d91c218@git.kernel.org> Date: Wed, 4 Mar 2015 14:55:13 -0800 From: tip-bot for Denys Vlasenko <tipbot@...or.com> To: linux-tip-commits@...r.kernel.org Cc: fweisbec@...il.com, wad@...omium.org, bp@...en8.de, mingo@...nel.org, linux-kernel@...r.kernel.org, dvlasenk@...hat.com, hpa@...or.com, oleg@...hat.com, ast@...mgrid.com, torvalds@...ux-foundation.org, luto@...capital.net, keescook@...omium.org, tglx@...utronix.de Subject: [tip:x86/asm] x86/asm/entry/64: Move 'save_paranoid' and ' ret_from_fork' closer to their users Commit-ID: 1eeb207f870f746a863e5c59321d837d2d91c218 Gitweb: http://git.kernel.org/tip/1eeb207f870f746a863e5c59321d837d2d91c218 Author: Denys Vlasenko <dvlasenk@...hat.com> AuthorDate: Thu, 26 Feb 2015 14:40:33 -0800 Committer: Ingo Molnar <mingo@...nel.org> CommitDate: Wed, 4 Mar 2015 22:50:51 +0100 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@...hat.com> Signed-off-by: Andy Lutomirski <luto@...capital.net> Cc: Alexei Starovoitov <ast@...mgrid.com> Cc: Borislav Petkov <bp@...en8.de> Cc: Frederic Weisbecker <fweisbec@...il.com> Cc: H. Peter Anvin <hpa@...or.com> Cc: Kees Cook <keescook@...omium.org> Cc: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Oleg Nesterov <oleg@...hat.com> Cc: Thomas Gleixner <tglx@...utronix.de> Cc: Will Drewry <wad@...omium.org> Link: http://lkml.kernel.org/r/6446bbfe4094532623a5b83779b7015fec167a9d.1424989793.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@...nel.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 e5cbfbb..9e33d49 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. * @@ -582,6 +529,43 @@ 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 * single cache line on all modern x86 implementations. @@ -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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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