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96d4f267e4
linux_dsm_epyc7002/arch/c6x/kernel/signal.c
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function 
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>
2019-01-03 18:57:57 -08:00

327 lines
8.0 KiB
C
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/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
/*
* Do a signal return, undo the signal stack.
*/
#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
struct rt_sigframe {
struct siginfo __user *pinfo;
void __user *puc;
struct siginfo info;
struct ucontext uc;
unsigned long retcode[RETCODE_SIZE >> 2];
};
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
int err = 0;
/* The access_ok check was done by caller, so use __get_user here */
#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a dword boundary,
* 'sp' should be dword aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->sp & 7)
goto badframe;
frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
return regs->a4;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
err |= __put_user(mask, &sc->sc_mask);
/* The access_ok check was done by caller, so use __put_user here */
#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
unsigned long framesize)
{
unsigned long sp = sigsp(regs->sp, ksig);
/*
* No matter what happens, 'sp' must be dword
* aligned. Otherwise, nasty things will happen
*/
return (void __user *)((sp - framesize) & ~7);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
unsigned long __user *retcode;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
return -EFAULT;
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Clear all the bits of the ucontext we don't use. */
err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace */
retcode = (unsigned long __user *) &frame->retcode;
/* The access_ok check was done above, so use __put_user here */
#define COPY(x) (err |= __put_user(x, retcode++))
COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
/* MVK __NR_rt_sigreturn,B0 */
COPY(0x10000000UL); /* SWE */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
#undef COPY
if (err)
return -EFAULT;
flush_icache_range((unsigned long) &frame->retcode,
(unsigned long) &frame->retcode + RETCODE_SIZE);
retcode = (unsigned long __user *) &frame->retcode;
/* Change user context to branch to signal handler */
regs->sp = (unsigned long) frame - 8;
regs->b3 = (unsigned long) retcode;
regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
/* Give the signal number to the handler */
regs->a4 = ksig->sig;
/*
* For realtime signals we must also set the second and third
* arguments for the signal handler.
* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
*/
regs->b4 = (unsigned long)&frame->info;
regs->a6 = (unsigned long)&frame->uc;
return 0;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->a4) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
do_restart:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
}
}
/*
* handle the actual delivery of a signal to userspace
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
int syscall)
{
int ret;
/* Are we from a system call? */
if (syscall) {
/* If so, check system call restarting.. */
switch (regs->a4) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
}
}
/* Set up the stack frame */
ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
signal_setup_done(ret, ksig, 0);
}
/*
* handle a potential signal
*/
static void do_signal(struct pt_regs *regs, int syscall)
{
struct ksignal ksig;
/* we want the common case to go fast, which is why we may in certain
* cases get here from kernel mode */
if (!user_mode(regs))
return;
if (get_signal(&ksig)) {
handle_signal(&ksig, regs, syscall);
return;
}
/* did we come from a system call? */
if (syscall) {
/* restart the system call - no handlers present */
switch (regs->a4) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
case -ERESTART_RESTARTBLOCK:
regs->a4 = regs->orig_a4;
regs->b0 = __NR_restart_syscall;
regs->pc -= 4;
break;
}
}
/* if there's no signal to deliver, we just put the saved sigmask
* back */
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
*/
asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
int syscall)
{
/* deal with pending signal delivery */
if (thread_info_flags & (1 << TIF_SIGPENDING))
do_signal(regs, syscall);
if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
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