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author | Christophe Leroy | 2019-01-31 11:09:00 +0100 |
---|---|---|
committer | Michael Ellerman | 2019-02-23 12:31:40 +0100 |
commit | a7916a1de526162d73e894b6d3ebd895d4302078 (patch) | |
tree | d34624a17b6475cc0e45bafdde2c6d51b6a70626 /arch/powerpc/kernel/process.c | |
parent | powerpc: Activate CONFIG_THREAD_INFO_IN_TASK (diff) | |
download | kernel-qcow2-linux-a7916a1de526162d73e894b6d3ebd895d4302078.tar.gz kernel-qcow2-linux-a7916a1de526162d73e894b6d3ebd895d4302078.tar.xz kernel-qcow2-linux-a7916a1de526162d73e894b6d3ebd895d4302078.zip |
powerpc: regain entire stack space
thread_info is not anymore in the stack, so the entire stack
can now be used.
There is also no risk anymore of corrupting task_cpu(p) with a
stack overflow so the patch removes the test.
When doing this, an explicit test for NULL stack pointer is
needed in validate_sp() as it is not anymore implicitely covered
by the sizeof(thread_info) gap.
In the meantime, with the previous patch all pointers to the stacks
are not anymore pointers to thread_info so this patch changes them
to void*
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/process.c')
-rw-r--r-- | arch/powerpc/kernel/process.c | 32 |
1 files changed, 13 insertions, 19 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index fd07711035bd..dd9e0d5386ee 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1691,8 +1691,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, sp -= STACK_FRAME_OVERHEAD; p->thread.ksp = sp; #ifdef CONFIG_PPC32 - p->thread.ksp_limit = (unsigned long)task_stack_page(p) + - _ALIGN_UP(sizeof(struct thread_info), 16); + p->thread.ksp_limit = (unsigned long)end_of_stack(p); #endif #ifdef CONFIG_HAVE_HW_BREAKPOINT p->thread.ptrace_bps[0] = NULL; @@ -1995,21 +1994,14 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, unsigned long stack_page; unsigned long cpu = task_cpu(p); - /* - * Avoid crashing if the stack has overflowed and corrupted - * task_cpu(p), which is in the thread_info struct. - */ - if (cpu < NR_CPUS && cpu_possible(cpu)) { - stack_page = (unsigned long) hardirq_ctx[cpu]; - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) - return 1; - - stack_page = (unsigned long) softirq_ctx[cpu]; - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) - return 1; - } + stack_page = (unsigned long)hardirq_ctx[cpu]; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + + stack_page = (unsigned long)softirq_ctx[cpu]; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + return 0; } @@ -2018,8 +2010,10 @@ int validate_sp(unsigned long sp, struct task_struct *p, { unsigned long stack_page = (unsigned long)task_stack_page(p); - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) + if (sp < THREAD_SIZE) + return 0; + + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; return valid_irq_stack(sp, p, nbytes); |