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![Peter Zijlstra](/assets/img/avatar_default.png)
struct perf_sample_data lives on-stack, we should be careful about it's size. Furthermore, the pt_regs copy in there is only because x86_64 is a trainwreck, solve it differently. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Link: https://lkml.kernel.org/r/20201030151955.258178461@infradead.org
68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/perf_event.h>
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#include <linux/perf_regs.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/bug.h>
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#include <asm/ptrace.h>
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#include <asm/fpu/api.h>
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#include <asm/fpu/types.h>
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u64 perf_reg_value(struct pt_regs *regs, int idx)
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{
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freg_t fp;
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if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
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return regs->gprs[idx];
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if (idx >= PERF_REG_S390_FP0 && idx <= PERF_REG_S390_FP15) {
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if (!user_mode(regs))
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return 0;
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idx -= PERF_REG_S390_FP0;
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fp = MACHINE_HAS_VX ? *(freg_t *)(current->thread.fpu.vxrs + idx)
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: current->thread.fpu.fprs[idx];
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return fp.ui;
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}
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if (idx == PERF_REG_S390_MASK)
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return regs->psw.mask;
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if (idx == PERF_REG_S390_PC)
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return regs->psw.addr;
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WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX);
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return 0;
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}
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#define REG_RESERVED (~((1UL << PERF_REG_S390_MAX) - 1))
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int perf_reg_validate(u64 mask)
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{
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if (!mask || mask & REG_RESERVED)
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return -EINVAL;
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return 0;
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}
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u64 perf_reg_abi(struct task_struct *task)
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{
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if (test_tsk_thread_flag(task, TIF_31BIT))
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return PERF_SAMPLE_REGS_ABI_32;
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return PERF_SAMPLE_REGS_ABI_64;
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}
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void perf_get_regs_user(struct perf_regs *regs_user,
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struct pt_regs *regs)
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{
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/*
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* Use the regs from the first interruption and let
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* perf_sample_regs_intr() handle interrupts (regs == get_irq_regs()).
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*
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* Also save FPU registers for user-space tasks only.
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*/
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regs_user->regs = task_pt_regs(current);
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if (user_mode(regs_user->regs))
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save_fpu_regs();
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regs_user->abi = perf_reg_abi(current);
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}
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