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linux/arch/powerpc/include/asm/thread_info.h
Christophe Leroy dca5b1d69a powerpc/32: Implement validation of emergency stack 
VMAP stack added an emergency stack on powerpc/32 for when there is
a stack overflow, but failed to add stack validation for that
emergency stack. That validation is required for show stack.

Implement it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2439d50b019f758db4a6d7b238b06441ab109799.1724156805.git.christophe.leroy@csgroup.eu
2024-08-30 21:30:20 +10:00

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/* SPDX-License-Identifier: GPL-2.0 */
/* thread_info.h: PowerPC low-level thread information
* adapted from the i386 version by Paul Mackerras
*
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
* - Incorporating suggestions made by Linus Torvalds and Dave Miller
*/
#ifndef _ASM_POWERPC_THREAD_INFO_H
#define _ASM_POWERPC_THREAD_INFO_H
#include <asm/asm-const.h>
#include <asm/page.h>
#ifdef __KERNEL__
#if defined(CONFIG_KASAN) && CONFIG_THREAD_SHIFT < 15
#define MIN_THREAD_SHIFT (CONFIG_THREAD_SHIFT + 1)
#else
#define MIN_THREAD_SHIFT CONFIG_THREAD_SHIFT
#endif
#if defined(CONFIG_VMAP_STACK) && MIN_THREAD_SHIFT < PAGE_SHIFT
#define THREAD_SHIFT PAGE_SHIFT
#else
#define THREAD_SHIFT MIN_THREAD_SHIFT
#endif
#define THREAD_SIZE (1 << THREAD_SHIFT)
/*
* By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
* checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
* assembly.
*/
#ifdef CONFIG_VMAP_STACK
#define THREAD_ALIGN_SHIFT (THREAD_SHIFT + 1)
#else
#define THREAD_ALIGN_SHIFT THREAD_SHIFT
#endif
#define THREAD_ALIGN (1 << THREAD_ALIGN_SHIFT)
#ifndef __ASSEMBLY__
#include <linux/cache.h>
#include <asm/processor.h>
#include <asm/accounting.h>
#include <asm/ppc_asm.h>
#define SLB_PRELOAD_NR 16U
/*
* low level task data.
*/
struct thread_info {
int preempt_count; /* 0 => preemptable,
<0 => BUG */
#ifdef CONFIG_SMP
unsigned int cpu;
#endif
unsigned long local_flags; /* private flags for thread */
#ifdef CONFIG_LIVEPATCH_64
unsigned long *livepatch_sp;
#endif
#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC32)
struct cpu_accounting_data accounting;
#endif
unsigned char slb_preload_nr;
unsigned char slb_preload_tail;
u32 slb_preload_esid[SLB_PRELOAD_NR];
/* low level flags - has atomic operations done on it */
unsigned long flags ____cacheline_aligned_in_smp;
};
/*
* macros/functions for gaining access to the thread information structure
*/
#define INIT_THREAD_INFO(tsk) \
{ \
.preempt_count = INIT_PREEMPT_COUNT, \
.flags = 0, \
}
#define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
/* how to get the thread information struct from C */
extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
void arch_setup_new_exec(void);
#define arch_setup_new_exec arch_setup_new_exec
#endif /* __ASSEMBLY__ */
/*
* thread information flag bit numbers
*/
#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_SIGPENDING 1 /* signal pending */
#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
#define TIF_NOTIFY_SIGNAL 3 /* signal notifications exist */
#define TIF_SYSCALL_EMU 4 /* syscall emulation active */
#define TIF_RESTORE_TM 5 /* need to restore TM FP/VEC/VSX */
#define TIF_PATCH_PENDING 6 /* pending live patching update */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SINGLESTEP 8 /* singlestepping active */
#define TIF_SECCOMP 10 /* secure computing */
#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
#define TIF_NOERROR 12 /* Force successful syscall return */
#define TIF_NOTIFY_RESUME 13 /* callback before returning to user */
#define TIF_UPROBE 14 /* breakpointed or single-stepping */
#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */
#define TIF_EMULATE_STACK_STORE 16 /* Is an instruction emulation
for stack store? */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
#if defined(CONFIG_PPC64)
#define TIF_ELF2ABI 18 /* function descriptors must die! */
#endif
#define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_32BIT 20 /* 32 bit binary */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_NOTIFY_SIGNAL (1<<TIF_NOTIFY_SIGNAL)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_32BIT (1<<TIF_32BIT)
#define _TIF_RESTORE_TM (1<<TIF_RESTORE_TM)
#define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
#define _TIF_NOERROR (1<<TIF_NOERROR)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_UPROBE (1<<TIF_UPROBE)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_EMULATE_STACK_STORE (1<<TIF_EMULATE_STACK_STORE)
#define _TIF_SYSCALL_EMU (1<<TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_DOTRACE (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
_TIF_SYSCALL_EMU)
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
_TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
_TIF_NOTIFY_SIGNAL)
#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
/* Bits in local_flags */
/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
#define TLF_NAPPING 0 /* idle thread enabled NAP mode */
#define TLF_SLEEPING 1 /* suspend code enabled SLEEP mode */
#define TLF_LAZY_MMU 3 /* tlb_batch is active */
#define TLF_RUNLATCH 4 /* Is the runlatch enabled? */
#define _TLF_NAPPING (1 << TLF_NAPPING)
#define _TLF_SLEEPING (1 << TLF_SLEEPING)
#define _TLF_LAZY_MMU (1 << TLF_LAZY_MMU)
#define _TLF_RUNLATCH (1 << TLF_RUNLATCH)
#ifndef __ASSEMBLY__
static inline void clear_thread_local_flags(unsigned int flags)
{
struct thread_info *ti = current_thread_info();
ti->local_flags &= ~flags;
}
static inline bool test_thread_local_flags(unsigned int flags)
{
struct thread_info *ti = current_thread_info();
return (ti->local_flags & flags) != 0;
}
#ifdef CONFIG_COMPAT
#define is_32bit_task() (test_thread_flag(TIF_32BIT))
#define is_tsk_32bit_task(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT))
#define clear_tsk_compat_task(tsk) (clear_tsk_thread_flag(p, TIF_32BIT))
#else
#define is_32bit_task() (IS_ENABLED(CONFIG_PPC32))
#define is_tsk_32bit_task(tsk) (IS_ENABLED(CONFIG_PPC32))
#define clear_tsk_compat_task(tsk) do { } while (0)
#endif
#if defined(CONFIG_PPC64)
#define is_elf2_task() (test_thread_flag(TIF_ELF2ABI))
#else
#define is_elf2_task() (0)
#endif
/*
* Walks up the stack frames to make sure that the specified object is
* entirely contained by a single stack frame.
*
* Returns:
* GOOD_FRAME if within a frame
* BAD_STACK if placed across a frame boundary (or outside stack)
*/
static inline int arch_within_stack_frames(const void * const stack,
const void * const stackend,
const void *obj, unsigned long len)
{
const void *params;
const void *frame;
params = *(const void * const *)current_stack_pointer + STACK_FRAME_PARAMS;
frame = **(const void * const * const *)current_stack_pointer;
/*
* low -----------------------------------------------------------> high
* [backchain][metadata][params][local vars][saved registers][backchain]
* ^------------------------------------^
* | allows copies only in this region |
* | |
* params frame
* The metadata region contains the saved LR, CR etc.
*/
while (stack <= frame && frame < stackend) {
if (obj + len <= frame)
return obj >= params ? GOOD_FRAME : BAD_STACK;
params = frame + STACK_FRAME_PARAMS;
frame = *(const void * const *)frame;
}
return BAD_STACK;
}
#ifdef CONFIG_PPC32
extern void *emergency_ctx[];
#endif
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_THREAD_INFO_H */
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