Messages in this thread | | | Date | Fri, 25 Oct 2013 14:14:41 +0100 | From | Will Deacon <> | Subject | Re: [PATCH 1/2] ARM64: perf: add support for perf registers API |
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On Fri, Oct 18, 2013 at 03:54:37PM +0100, Jean Pihet wrote: > From: Jean Pihet <jean.pihet@newoldbits.com> > > This patch implements the functions required for the perf registers API, > allowing the perf tool to interface kernel register dumps with libunwind > in order to provide userspace backtracing. > Only the general purpose user space registers are exported, i.e.: > PERF_REG_ARM_X0, > ... > PERF_REG_ARM_X28, > PERF_REG_ARM_FP, > PERF_REG_ARM_LR, > PERF_REG_ARM_SP, > PERF_REG_ARM_PC > and not the PERF_REG_ARM_V* registers.
[...]
> diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c > new file mode 100644 > index 0000000..bbcf63c > --- /dev/null > +++ b/arch/arm64/kernel/perf_regs.c > @@ -0,0 +1,29 @@ > +#include <linux/errno.h> > +#include <linux/kernel.h> > +#include <linux/perf_event.h> > +#include <linux/bug.h> > +#include <asm/perf_regs.h> > +#include <asm/ptrace.h> > + > +u64 perf_reg_value(struct pt_regs *regs, int idx) > +{ > + if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM_MAX)) > + return 0; > + > + return regs->regs[idx]; > +} > + > +#define REG_RESERVED (~((1ULL << PERF_REG_ARM_MAX) - 1)) > + > +int perf_reg_validate(u64 mask) > +{ > + if (!mask || mask & REG_RESERVED) > + return -EINVAL; > + > + return 0; > +} > + > +u64 perf_reg_abi(struct task_struct *task) > +{ > + return PERF_SAMPLE_REGS_ABI_64; > +}
You need to deal with compat (AArch32) tasks here too, which means providing something compatible with what we do on arch/arm/ depending on the thread flags.
Will
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