Alexey Brodkin
508a750fe6
commit f51e2f1911122879eefefa4c592dea8bf794b39c upstream. Currently instruction_pointer() returns pt_regs->ret and so return value is of type "long", which implicitly stands for "signed long". While that's perfectly fine when dealing with 32-bit values if return value of instruction_pointer() gets assigned to 64-bit variable sign extension may happen. And at least in one real use-case it happens already. In perf_prepare_sample() return value of perf_instruction_pointer() (which is an alias to instruction_pointer() in case of ARC) is assigned to (struct perf_sample_data)->ip (which type is "u64"). And what we see if instuction pointer points to user-space application that in case of ARC lays below 0x8000_0000 "ip" gets set properly with leading 32 zeros. But if instruction pointer points to kernel address space that starts from 0x8000_0000 then "ip" is set with 32 leadig "f"-s. I.e. id instruction_pointer() returns 0x8100_0000, "ip" will be assigned with 0xffff_ffff__8100_0000. Which is obviously wrong. In particular that issuse broke output of perf, because perf was unable to associate addresses like 0xffff_ffff__8100_0000 with anything from /proc/kallsyms. That's what we used to see: ----------->8---------- 6.27% ls [unknown] [k] 0xffffffff8046c5cc 2.96% ls libuClibc-0.9.34-git.so [.] memcpy 2.25% ls libuClibc-0.9.34-git.so [.] memset 1.66% ls [unknown] [k] 0xffffffff80666536 1.54% ls libuClibc-0.9.34-git.so [.] 0x000224d6 1.18% ls libuClibc-0.9.34-git.so [.] 0x00022472 ----------->8---------- With that change perf output looks much better now: ----------->8---------- 8.21% ls [kernel.kallsyms] [k] memset 3.52% ls libuClibc-0.9.34-git.so [.] memcpy 2.11% ls libuClibc-0.9.34-git.so [.] malloc 1.88% ls libuClibc-0.9.34-git.so [.] memset 1.64% ls [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore 1.41% ls [kernel.kallsyms] [k] __d_lookup_rcu ----------->8---------- Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: arc-linux-dev@synopsys.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
133 lines
3.0 KiB
C
133 lines
3.0 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Amit Bhor, Sameer Dhavale: Codito Technologies 2004
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*/
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#ifndef __ASM_ARC_PTRACE_H
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#define __ASM_ARC_PTRACE_H
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#include <uapi/asm/ptrace.h>
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#ifndef __ASSEMBLY__
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/* THE pt_regs: Defines how regs are saved during entry into kernel */
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struct pt_regs {
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/*
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* 1 word gutter after reg-file has been saved
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* Technically not needed, Since SP always points to a "full" location
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* (vs. "empty"). But pt_regs is shared with tools....
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*/
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long res;
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/* Real registers */
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long bta; /* bta_l1, bta_l2, erbta */
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long lp_start;
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long lp_end;
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long lp_count;
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long status32; /* status32_l1, status32_l2, erstatus */
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long ret; /* ilink1, ilink2 or eret */
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long blink;
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long fp;
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long r26; /* gp */
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long r12;
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long r11;
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long r10;
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long r9;
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long r8;
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long r7;
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long r6;
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long r5;
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long r4;
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long r3;
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long r2;
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long r1;
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long r0;
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long sp; /* user/kernel sp depending on where we came from */
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long orig_r0;
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/*to distinguish bet excp, syscall, irq */
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union {
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struct {
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#ifdef CONFIG_CPU_BIG_ENDIAN
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/* so that assembly code is same for LE/BE */
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unsigned long orig_r8:16, event:16;
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#else
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unsigned long event:16, orig_r8:16;
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#endif
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};
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long orig_r8_word;
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};
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};
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/* Callee saved registers - need to be saved only when you are scheduled out */
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struct callee_regs {
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long res; /* Again this is not needed */
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long r25;
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long r24;
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long r23;
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long r22;
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long r21;
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long r20;
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long r19;
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long r18;
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long r17;
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long r16;
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long r15;
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long r14;
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long r13;
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};
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#define instruction_pointer(regs) (unsigned long)((regs)->ret)
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#define profile_pc(regs) instruction_pointer(regs)
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/* return 1 if user mode or 0 if kernel mode */
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#define user_mode(regs) (regs->status32 & STATUS_U_MASK)
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#define user_stack_pointer(regs)\
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({ unsigned int sp; \
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if (user_mode(regs)) \
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sp = (regs)->sp;\
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else \
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sp = -1; \
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sp; \
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})
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/* return 1 if PC in delay slot */
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#define delay_mode(regs) ((regs->status32 & STATUS_DE_MASK) == STATUS_DE_MASK)
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#define in_syscall(regs) (regs->event & orig_r8_IS_SCALL)
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#define in_brkpt_trap(regs) (regs->event & orig_r8_IS_BRKPT)
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#define syscall_wont_restart(regs) (regs->event |= orig_r8_IS_SCALL_RESTARTED)
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#define syscall_restartable(regs) !(regs->event & orig_r8_IS_SCALL_RESTARTED)
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#define current_pt_regs() \
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({ \
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/* open-coded current_thread_info() */ \
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register unsigned long sp asm ("sp"); \
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unsigned long pg_start = (sp & ~(THREAD_SIZE - 1)); \
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(struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \
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})
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static inline long regs_return_value(struct pt_regs *regs)
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{
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return regs->r0;
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}
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#endif /* !__ASSEMBLY__ */
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#define orig_r8_IS_SCALL 0x0001
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#define orig_r8_IS_SCALL_RESTARTED 0x0002
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#define orig_r8_IS_BRKPT 0x0004
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#define orig_r8_IS_EXCPN 0x0008
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#define orig_r8_IS_IRQ1 0x0010
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#define orig_r8_IS_IRQ2 0x0020
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#endif /* __ASM_PTRACE_H */
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