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9afc5eee65
Christoph Hellwig suggested a slightly different path for handling backwards compatibility with the 32-bit time_t based system calls: Rather than simply reusing the compat_sys_* entry points on 32-bit architectures unchanged, we get rid of those entry points and the compat_time types by renaming them to something that makes more sense on 32-bit architectures (which don't have a compat mode otherwise), and then share the entry points under the new name with the 64-bit architectures that use them for implementing the compatibility. The following types and interfaces are renamed here, and moved from linux/compat_time.h to linux/time32.h: old new --- --- compat_time_t old_time32_t struct compat_timeval struct old_timeval32 struct compat_timespec struct old_timespec32 struct compat_itimerspec struct old_itimerspec32 ns_to_compat_timeval() ns_to_old_timeval32() get_compat_itimerspec64() get_old_itimerspec32() put_compat_itimerspec64() put_old_itimerspec32() compat_get_timespec64() get_old_timespec32() compat_put_timespec64() put_old_timespec32() As we already have aliases in place, this patch addresses only the instances that are relevant to the system call interface in particular, not those that occur in device drivers and other modules. Those will get handled separately, while providing the 64-bit version of the respective interfaces. I'm not renaming the timex, rusage and itimerval structures, as we are still debating what the new interface will look like, and whether we will need a replacement at all. This also doesn't change the names of the syscall entry points, which can be done more easily when we actually switch over the 32-bit architectures to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix. Suggested-by: Christoph Hellwig <hch@infradead.org> Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/ Signed-off-by: Arnd Bergmann <arnd@arndb.de>
132 lines
3.0 KiB
C
132 lines
3.0 KiB
C
/**
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* Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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**/
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#include <linux/time.h>
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <asm/processor.h>
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#include <linux/uaccess.h>
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#include <asm/compat.h>
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#include <asm/oprofile_impl.h>
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#define STACK_SP(STACK) *(STACK)
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#define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
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#define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
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#ifdef CONFIG_PPC64
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#define STACK_LR(STACK) STACK_LR64(STACK)
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#else
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#define STACK_LR(STACK) STACK_LR32(STACK)
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#endif
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static unsigned int user_getsp32(unsigned int sp, int is_first)
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{
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unsigned int stack_frame[2];
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void __user *p = compat_ptr(sp);
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if (!access_ok(VERIFY_READ, p, sizeof(stack_frame)))
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return 0;
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/*
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* The most likely reason for this is that we returned -EFAULT,
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* which means that we've done all that we can do from
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* interrupt context.
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*/
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if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR32(stack_frame));
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/*
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* We do not enforce increasing stack addresses here because
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* we may transition to a different stack, eg a signal handler.
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*/
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return STACK_SP(stack_frame);
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}
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#ifdef CONFIG_PPC64
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static unsigned long user_getsp64(unsigned long sp, int is_first)
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{
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unsigned long stack_frame[3];
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if (!access_ok(VERIFY_READ, (void __user *)sp, sizeof(stack_frame)))
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return 0;
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if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
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sizeof(stack_frame)))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR64(stack_frame));
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return STACK_SP(stack_frame);
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}
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#endif
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static unsigned long kernel_getsp(unsigned long sp, int is_first)
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{
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unsigned long *stack_frame = (unsigned long *)sp;
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if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR(stack_frame));
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/*
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* We do not enforce increasing stack addresses here because
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* we might be transitioning from an interrupt stack to a kernel
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* stack. validate_sp() is designed to understand this, so just
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* use it.
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*/
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return STACK_SP(stack_frame);
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}
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void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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unsigned long sp = regs->gpr[1];
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int first_frame = 1;
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/* We ditch the top stackframe so need to loop through an extra time */
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depth += 1;
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if (!user_mode(regs)) {
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while (depth--) {
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sp = kernel_getsp(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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} else {
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pagefault_disable();
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#ifdef CONFIG_PPC64
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if (!is_32bit_task()) {
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while (depth--) {
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sp = user_getsp64(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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pagefault_enable();
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return;
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}
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#endif
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while (depth--) {
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sp = user_getsp32(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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pagefault_enable();
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}
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}
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