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186 lines
4.4 KiB
186 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* arm64 callchain support |
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* |
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* Copyright (C) 2015 ARM Limited |
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*/ |
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#include <linux/perf_event.h> |
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#include <linux/uaccess.h> |
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#include <asm/pointer_auth.h> |
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#include <asm/stacktrace.h> |
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struct frame_tail { |
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struct frame_tail __user *fp; |
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unsigned long lr; |
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} __attribute__((packed)); |
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/* |
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* Get the return address for a single stackframe and return a pointer to the |
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* next frame tail. |
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*/ |
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static struct frame_tail __user * |
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user_backtrace(struct frame_tail __user *tail, |
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struct perf_callchain_entry_ctx *entry) |
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{ |
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struct frame_tail buftail; |
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unsigned long err; |
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unsigned long lr; |
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/* Also check accessibility of one struct frame_tail beyond */ |
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if (!access_ok(tail, sizeof(buftail))) |
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return NULL; |
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pagefault_disable(); |
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err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail)); |
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pagefault_enable(); |
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if (err) |
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return NULL; |
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lr = ptrauth_strip_insn_pac(buftail.lr); |
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perf_callchain_store(entry, lr); |
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/* |
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* Frame pointers should strictly progress back up the stack |
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* (towards higher addresses). |
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*/ |
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if (tail >= buftail.fp) |
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return NULL; |
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return buftail.fp; |
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} |
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#ifdef CONFIG_COMPAT |
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/* |
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* The registers we're interested in are at the end of the variable |
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* length saved register structure. The fp points at the end of this |
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* structure so the address of this struct is: |
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* (struct compat_frame_tail *)(xxx->fp)-1 |
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* |
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* This code has been adapted from the ARM OProfile support. |
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*/ |
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struct compat_frame_tail { |
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compat_uptr_t fp; /* a (struct compat_frame_tail *) in compat mode */ |
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u32 sp; |
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u32 lr; |
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} __attribute__((packed)); |
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static struct compat_frame_tail __user * |
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compat_user_backtrace(struct compat_frame_tail __user *tail, |
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struct perf_callchain_entry_ctx *entry) |
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{ |
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struct compat_frame_tail buftail; |
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unsigned long err; |
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/* Also check accessibility of one struct frame_tail beyond */ |
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if (!access_ok(tail, sizeof(buftail))) |
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return NULL; |
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pagefault_disable(); |
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err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail)); |
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pagefault_enable(); |
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if (err) |
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return NULL; |
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perf_callchain_store(entry, buftail.lr); |
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/* |
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* Frame pointers should strictly progress back up the stack |
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* (towards higher addresses). |
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*/ |
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if (tail + 1 >= (struct compat_frame_tail __user *) |
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compat_ptr(buftail.fp)) |
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return NULL; |
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return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1; |
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} |
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#endif /* CONFIG_COMPAT */ |
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void perf_callchain_user(struct perf_callchain_entry_ctx *entry, |
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struct pt_regs *regs) |
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{ |
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if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { |
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/* We don't support guest os callchain now */ |
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return; |
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} |
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perf_callchain_store(entry, regs->pc); |
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if (!compat_user_mode(regs)) { |
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/* AARCH64 mode */ |
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struct frame_tail __user *tail; |
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tail = (struct frame_tail __user *)regs->regs[29]; |
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while (entry->nr < entry->max_stack && |
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tail && !((unsigned long)tail & 0xf)) |
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tail = user_backtrace(tail, entry); |
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} else { |
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#ifdef CONFIG_COMPAT |
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/* AARCH32 compat mode */ |
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struct compat_frame_tail __user *tail; |
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tail = (struct compat_frame_tail __user *)regs->compat_fp - 1; |
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while ((entry->nr < entry->max_stack) && |
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tail && !((unsigned long)tail & 0x3)) |
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tail = compat_user_backtrace(tail, entry); |
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#endif |
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} |
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} |
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/* |
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* Gets called by walk_stackframe() for every stackframe. This will be called |
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* whist unwinding the stackframe and is like a subroutine return so we use |
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* the PC. |
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*/ |
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static bool callchain_trace(void *data, unsigned long pc) |
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{ |
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struct perf_callchain_entry_ctx *entry = data; |
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perf_callchain_store(entry, pc); |
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return true; |
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} |
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void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, |
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struct pt_regs *regs) |
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{ |
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struct stackframe frame; |
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if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { |
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/* We don't support guest os callchain now */ |
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return; |
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} |
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start_backtrace(&frame, regs->regs[29], regs->pc); |
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walk_stackframe(current, &frame, callchain_trace, entry); |
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} |
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unsigned long perf_instruction_pointer(struct pt_regs *regs) |
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{ |
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if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) |
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return perf_guest_cbs->get_guest_ip(); |
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return instruction_pointer(regs); |
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} |
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unsigned long perf_misc_flags(struct pt_regs *regs) |
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{ |
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int misc = 0; |
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if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { |
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if (perf_guest_cbs->is_user_mode()) |
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misc |= PERF_RECORD_MISC_GUEST_USER; |
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else |
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misc |= PERF_RECORD_MISC_GUEST_KERNEL; |
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} else { |
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if (user_mode(regs)) |
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misc |= PERF_RECORD_MISC_USER; |
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else |
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misc |= PERF_RECORD_MISC_KERNEL; |
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} |
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return misc; |
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}
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