diff options
Diffstat (limited to 'arch/powerpc/perf/callchain.c')
-rw-r--r-- | arch/powerpc/perf/callchain.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c new file mode 100644 index 0000000000..6b4434dd0f --- /dev/null +++ b/arch/powerpc/perf/callchain.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Performance counter callchain support - powerpc architecture code + * + * Copyright © 2009 Paul Mackerras, IBM Corporation. + */ +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/perf_event.h> +#include <linux/percpu.h> +#include <linux/uaccess.h> +#include <linux/mm.h> +#include <asm/ptrace.h> +#include <asm/sigcontext.h> +#include <asm/ucontext.h> +#include <asm/vdso.h> +#include <asm/pte-walk.h> + +#include "callchain.h" + +/* + * Is sp valid as the address of the next kernel stack frame after prev_sp? + * The next frame may be in a different stack area but should not go + * back down in the same stack area. + */ +static int valid_next_sp(unsigned long sp, unsigned long prev_sp) +{ + if (sp & 0xf) + return 0; /* must be 16-byte aligned */ + if (!validate_sp(sp, current)) + return 0; + if (sp >= prev_sp + STACK_FRAME_MIN_SIZE) + return 1; + /* + * sp could decrease when we jump off an interrupt stack + * back to the regular process stack. + */ + if ((sp & ~(THREAD_SIZE - 1)) != (prev_sp & ~(THREAD_SIZE - 1))) + return 1; + return 0; +} + +void __no_sanitize_address +perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) +{ + unsigned long sp, next_sp; + unsigned long next_ip; + unsigned long lr; + long level = 0; + unsigned long *fp; + + lr = regs->link; + sp = regs->gpr[1]; + perf_callchain_store(entry, perf_instruction_pointer(regs)); + + if (!validate_sp(sp, current)) + return; + + for (;;) { + fp = (unsigned long *) sp; + next_sp = fp[0]; + + if (next_sp == sp + STACK_INT_FRAME_SIZE && + validate_sp_size(sp, current, STACK_INT_FRAME_SIZE) && + fp[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) { + /* + * This looks like an interrupt frame for an + * interrupt that occurred in the kernel + */ + regs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS); + next_ip = regs->nip; + lr = regs->link; + level = 0; + perf_callchain_store_context(entry, PERF_CONTEXT_KERNEL); + + } else { + if (level == 0) + next_ip = lr; + else + next_ip = fp[STACK_FRAME_LR_SAVE]; + + /* + * We can't tell which of the first two addresses + * we get are valid, but we can filter out the + * obviously bogus ones here. We replace them + * with 0 rather than removing them entirely so + * that userspace can tell which is which. + */ + if ((level == 1 && next_ip == lr) || + (level <= 1 && !kernel_text_address(next_ip))) + next_ip = 0; + + ++level; + } + + perf_callchain_store(entry, next_ip); + if (!valid_next_sp(next_sp, sp)) + return; + sp = next_sp; + } +} + +void +perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) +{ + if (!is_32bit_task()) + perf_callchain_user_64(entry, regs); + else + perf_callchain_user_32(entry, regs); +} |