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authorChristophe Leroy <christophe.leroy@c-s.fr>2019-01-31 13:08:58 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2019-02-23 14:31:40 +0300
commited1cd6deb013a11959d17a94e35ce159197632da (patch)
treefcfdc0de67e7753db653d06938d939fa0f0e924f /arch/powerpc/kernel/irq.c
parent7aef376679a428c6b7792fb4ce93364fd02caad4 (diff)
downloadlinux-ed1cd6deb013a11959d17a94e35ce159197632da.tar.xz
powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
This patch activates CONFIG_THREAD_INFO_IN_TASK which moves the thread_info into task_struct. Moving thread_info into task_struct has the following advantages: - It protects thread_info from corruption in the case of stack overflows. - Its address is harder to determine if stack addresses are leaked, making a number of attacks more difficult. This has the following consequences: - thread_info is now located at the beginning of task_struct. - The 'cpu' field is now in task_struct, and only exists when CONFIG_SMP is active. - thread_info doesn't have anymore the 'task' field. This patch: - Removes all recopy of thread_info struct when the stack changes. - Changes the CURRENT_THREAD_INFO() macro to point to current. - Selects CONFIG_THREAD_INFO_IN_TASK. - Modifies raw_smp_processor_id() to get ->cpu from current without including linux/sched.h to avoid circular inclusion and without including asm/asm-offsets.h to avoid symbol names duplication between ASM constants and C constants. - Modifies klp_init_thread_info() to take a task_struct pointer argument. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Add task_stack.h to livepatch.h to fix build fails] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/irq.c')
-rw-r--r--arch/powerpc/kernel/irq.c79
1 files changed, 1 insertions, 78 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 531e9ef153c0..85c48911938a 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -673,24 +673,9 @@ void do_IRQ(struct pt_regs *regs)
set_irq_regs(old_regs);
return;
}
-
- /* Prepare the thread_info in the irq stack */
- irqtp->task = curtp->task;
- irqtp->flags = 0;
-
- /* Copy the preempt_count so that the [soft]irq checks work. */
- irqtp->preempt_count = curtp->preempt_count;
-
/* Switch stack and call */
call_do_irq(regs, irqtp);
- /* Restore stack limit */
- irqtp->task = NULL;
-
- /* Copy back updates to the thread_info */
- if (irqtp->flags)
- set_bits(irqtp->flags, &curtp->flags);
-
set_irq_regs(old_regs);
}
@@ -698,85 +683,23 @@ void __init init_IRQ(void)
{
if (ppc_md.init_IRQ)
ppc_md.init_IRQ();
-
- exc_lvl_ctx_init();
-
- irq_ctx_init();
}
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
struct thread_info *critirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *dbgirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
-
-void exc_lvl_ctx_init(void)
-{
- struct thread_info *tp;
- int i, cpu_nr;
-
- for_each_possible_cpu(i) {
-#ifdef CONFIG_PPC64
- cpu_nr = i;
-#else
-#ifdef CONFIG_SMP
- cpu_nr = get_hard_smp_processor_id(i);
-#else
- cpu_nr = 0;
-#endif
-#endif
-
- tp = critirq_ctx[cpu_nr];
- tp->cpu = cpu_nr;
- tp->preempt_count = 0;
-
-#ifdef CONFIG_BOOKE
- tp = dbgirq_ctx[cpu_nr];
- tp->cpu = cpu_nr;
- tp->preempt_count = 0;
-
- tp = mcheckirq_ctx[cpu_nr];
- tp->cpu = cpu_nr;
- tp->preempt_count = HARDIRQ_OFFSET;
-#endif
- }
-}
#endif
struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
-void irq_ctx_init(void)
-{
- struct thread_info *tp;
- int i;
-
- for_each_possible_cpu(i) {
- tp = softirq_ctx[i];
- tp->cpu = i;
- klp_init_thread_info(tp);
-
- tp = hardirq_ctx[i];
- tp->cpu = i;
- klp_init_thread_info(tp);
- }
-}
-
void do_softirq_own_stack(void)
{
- struct thread_info *curtp, *irqtp;
+ struct thread_info *irqtp;
- curtp = current_thread_info();
irqtp = softirq_ctx[smp_processor_id()];
- irqtp->task = curtp->task;
- irqtp->flags = 0;
call_do_softirq(irqtp);
- irqtp->task = NULL;
-
- /* Set any flag that may have been set on the
- * alternate stack
- */
- if (irqtp->flags)
- set_bits(irqtp->flags, &curtp->flags);
}
irq_hw_number_t virq_to_hw(unsigned int virq)