tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
arch/tile: provide PT_FLAGS_COMPAT value in pt_regs
This flag is set for ptrace GETREGS or PEEKUSER for processes
that are COMPAT, i.e. 32-bit. This allows things like strace
to easily discover what personality to use, for example.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
+46
-17
+6
arch/tile/include/uapi/asm/ptrace.h
+6
arch/tile/include/uapi/asm/ptrace.h
···
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#define PTRACE_O_TRACEMIGRATE 0x00010000
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#define PTRACE_EVENT_MIGRATE 16
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/*
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* Flag bits in pt_regs.flags that are part of the ptrace API.
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* We start our numbering higher up to avoid confusion with the
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* non-ABI kernel-internal values that use the low 16 bits.
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*/
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#define PT_FLAGS_COMPAT 0x10000 /* process is an -m32 compat process */
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#endif /* _UAPI_ASM_TILE_PTRACE_H */
+40
-17
arch/tile/kernel/ptrace.c
+40
-17
arch/tile/kernel/ptrace.c
···
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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}
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+
/*
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* Get registers from task and ready the result for userspace.
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* Note that we localize the API issues to getregs() and putregs() at
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* some cost in performance, e.g. we need a full pt_regs copy for
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* PEEKUSR, and two copies for POKEUSR. But in general we expect
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* GETREGS/PUTREGS to be the API of choice anyway.
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*/
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static char *getregs(struct task_struct *child, struct pt_regs *uregs)
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{
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*uregs = *task_pt_regs(child);
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+
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/* Set up flags ABI bits. */
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uregs->flags = 0;
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#ifdef CONFIG_COMPAT
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if (task_thread_info(child)->status & TS_COMPAT)
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uregs->flags |= PT_FLAGS_COMPAT;
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#endif
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+
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return (char *)uregs;
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}
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+
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/* Put registers back to task. */
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static void putregs(struct task_struct *child, struct pt_regs *uregs)
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{
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struct pt_regs *regs = task_pt_regs(child);
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+
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/* Don't allow overwriting the kernel-internal flags word. */
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uregs->flags = regs->flags;
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+
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/* Only allow setting the ICS bit in the ex1 word. */
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uregs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(uregs->ex1));
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+
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*regs = *uregs;
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}
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+
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long arch_ptrace(struct task_struct *child, long request,
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unsigned long addr, unsigned long data)
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{
···
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long ret = -EIO;
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char *childreg;
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struct pt_regs copyregs;
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-
int ex1_offset;
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switch (request) {
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case PTRACE_PEEKUSR: /* Read register from pt_regs. */
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if (addr >= PTREGS_SIZE)
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break;
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-
childreg = (char *)task_pt_regs(child) + addr;
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childreg = getregs(child, ©regs) + addr;
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#ifdef CONFIG_COMPAT
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if (is_compat_task()) {
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if (addr & (sizeof(compat_long_t)-1))
···
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case PTRACE_POKEUSR: /* Write register in pt_regs. */
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if (addr >= PTREGS_SIZE)
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break;
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-
childreg = (char *)task_pt_regs(child) + addr;
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-
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/* Guard against overwrites of the privilege level. */
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ex1_offset = PTREGS_OFFSET_EX1;
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#if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)
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if (is_compat_task()) /* point at low word */
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ex1_offset += sizeof(compat_long_t);
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#endif
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if (addr == ex1_offset)
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data = PL_ICS_EX1(USER_PL, EX1_ICS(data));
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-
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childreg = getregs(child, ©regs) + addr;
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#ifdef CONFIG_COMPAT
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if (is_compat_task()) {
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if (addr & (sizeof(compat_long_t)-1))
···
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break;
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*(long *)childreg = data;
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}
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putregs(child, ©regs);
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ret = 0;
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break;
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case PTRACE_GETREGS: /* Get all registers from the child. */
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-
if (copy_to_user(datap, task_pt_regs(child),
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+
if (copy_to_user(datap, getregs(child, ©regs),
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sizeof(struct pt_regs)) == 0) {
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ret = 0;
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}
···
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case PTRACE_SETREGS: /* Set all registers in the child. */
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if (copy_from_user(©regs, datap,
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sizeof(struct pt_regs)) == 0) {
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-
copyregs.ex1 =
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-
PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));
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*task_pt_regs(child) = copyregs;
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+
putregs(child, ©regs);
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ret = 0;
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}
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break;