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96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ARM callchain support
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*
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* Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
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* Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
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*
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* This code is based on the ARM OProfile backtrace code.
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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/stacktrace.h>
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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 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 frame_tail {
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struct frame_tail __user *fp;
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unsigned long sp;
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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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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 >= buftail.fp)
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return NULL;
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return buftail.fp - 1;
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}
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void
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perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
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{
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struct frame_tail __user *tail;
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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->ARM_pc);
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if (!current->mm)
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return;
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tail = (struct frame_tail __user *)regs->ARM_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 = user_backtrace(tail, entry);
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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 int
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callchain_trace(struct stackframe *fr,
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void *data)
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{
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struct perf_callchain_entry_ctx *entry = data;
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perf_callchain_store(entry, fr->pc);
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return 0;
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}
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void
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perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
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{
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struct stackframe fr;
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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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arm_get_current_stackframe(regs, &fr);
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walk_stackframe(&fr, 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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