76f5df43ca
The 64-bit entry code was using six stack slots less by not saving/restoring registers which are callee-preserved according to the C ABI, and was not allocating space for them. Only when syscalls needed a complete "struct pt_regs" was the complete area allocated and filled in. As an additional twist, on interrupt entry a "slightly less truncated pt_regs" trick is used, to make nested interrupt stacks easier to unwind. This proved to be a source of significant obfuscation and subtle bugs. For example, 'stub_fork' had to pop the return address, extend the struct, save registers, and push return address back. Ugly. 'ia32_ptregs_common' pops return address and "returns" via jmp insn, throwing a wrench into CPU return stack cache. This patch changes the code to always allocate a complete "struct pt_regs" on the kernel stack. The saving of registers is still done lazily. "Partial pt_regs" trick on interrupt stack is retained. Macros which manipulate "struct pt_regs" on stack are reworked: - ALLOC_PT_GPREGS_ON_STACK allocates the structure. - SAVE_C_REGS saves to it those registers which are clobbered by C code. - SAVE_EXTRA_REGS saves to it all other registers. - Corresponding RESTORE_* and REMOVE_PT_GPREGS_FROM_STACK macros reverse it. 'ia32_ptregs_common', 'stub_fork' and friends lost their ugly dance with the return pointer. LOAD_ARGS32 in ia32entry.S now uses symbolic stack offsets instead of magic numbers. 'error_entry' and 'save_paranoid' now use SAVE_C_REGS + SAVE_EXTRA_REGS instead of having it open-coded yet again. Patch was run-tested: 64-bit executables, 32-bit executables, strace works. Timing tests did not show measurable difference in 32-bit and 64-bit syscalls. 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: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1423778052-21038-2-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/b89763d354aa23e670b9bdf3a40ae320320a7c2e.1424989793.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
87 خطوط
1.7 KiB
C
87 خطوط
1.7 KiB
C
#ifndef _ASM_X86_PTRACE_ABI_H
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#define _ASM_X86_PTRACE_ABI_H
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#ifdef __i386__
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#define EBX 0
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#define ECX 1
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#define EDX 2
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#define ESI 3
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#define EDI 4
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#define EBP 5
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#define EAX 6
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#define DS 7
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#define ES 8
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#define FS 9
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#define GS 10
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#define ORIG_EAX 11
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#define EIP 12
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#define CS 13
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#define EFL 14
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#define UESP 15
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#define SS 16
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#define FRAME_SIZE 17
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#else /* __i386__ */
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#if defined(__ASSEMBLY__) || defined(__FRAME_OFFSETS)
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#define R15 0
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#define R14 8
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#define R13 16
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#define R12 24
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#define RBP 32
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#define RBX 40
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/* arguments: interrupts/non tracing syscalls only save up to here*/
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#define R11 48
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#define R10 56
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#define R9 64
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#define R8 72
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#define RAX 80
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#define RCX 88
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#define RDX 96
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#define RSI 104
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#define RDI 112
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#define ORIG_RAX 120 /* = ERROR */
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/* end of arguments */
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/* cpu exception frame or undefined in case of fast syscall. */
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#define RIP 128
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#define CS 136
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#define EFLAGS 144
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#define RSP 152
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#define SS 160
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#endif /* __ASSEMBLY__ */
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/* top of stack page */
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#define FRAME_SIZE 168
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#endif /* !__i386__ */
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/* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
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#define PTRACE_GETREGS 12
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#define PTRACE_SETREGS 13
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#define PTRACE_GETFPREGS 14
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#define PTRACE_SETFPREGS 15
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#define PTRACE_GETFPXREGS 18
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#define PTRACE_SETFPXREGS 19
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#define PTRACE_OLDSETOPTIONS 21
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/* only useful for access 32bit programs / kernels */
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#define PTRACE_GET_THREAD_AREA 25
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#define PTRACE_SET_THREAD_AREA 26
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#ifdef __x86_64__
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# define PTRACE_ARCH_PRCTL 30
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#endif
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#define PTRACE_SYSEMU 31
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#define PTRACE_SYSEMU_SINGLESTEP 32
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#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#endif
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#endif /* _ASM_X86_PTRACE_ABI_H */
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