On Fri, Oct 18, 2013 at 03:54:37PM +0100, Jean Pihet wrote:
> From: Jean Pihet <jean.pi...@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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