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authorChristophe Leroy <christophe.leroy@c-s.fr>2019-01-31 10:08:58 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2019-02-23 22:31:40 +1100
commited1cd6deb013a11959d17a94e35ce159197632da (patch)
treefcfdc0de67e7753db653d06938d939fa0f0e924f /arch/powerpc/kernel
parent7aef376679a428c6b7792fb4ce93364fd02caad4 (diff)
downloadlinux-ed1cd6deb013a11959d17a94e35ce159197632da.tar.gz
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')
-rw-r--r--arch/powerpc/kernel/asm-offsets.c7
-rw-r--r--arch/powerpc/kernel/entry_32.S9
-rw-r--r--arch/powerpc/kernel/exceptions-64e.S11
-rw-r--r--arch/powerpc/kernel/head_32.S6
-rw-r--r--arch/powerpc/kernel/head_44x.S4
-rw-r--r--arch/powerpc/kernel/head_booke.h8
-rw-r--r--arch/powerpc/kernel/head_fsl_booke.S7
-rw-r--r--arch/powerpc/kernel/irq.c79
-rw-r--r--arch/powerpc/kernel/kgdb.c28
-rw-r--r--arch/powerpc/kernel/machine_kexec_64.c6
-rw-r--r--arch/powerpc/kernel/process.c2
-rw-r--r--arch/powerpc/kernel/setup-common.c2
-rw-r--r--arch/powerpc/kernel/setup_64.c21
-rw-r--r--arch/powerpc/kernel/smp.c2
14 files changed, 24 insertions, 168 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index ca55027f47a4..ca3fb836cbb9 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -13,6 +13,8 @@
* 2 of the License, or (at your option) any later version.
*/
+#define GENERATING_ASM_OFFSETS /* asm/smp.h */
+
#include <linux/compat.h>
#include <linux/signal.h>
#include <linux/sched.h>
@@ -97,6 +99,9 @@ int main(void)
#endif
#endif /* CONFIG_PPC64 */
OFFSET(TASK_STACK, task_struct, stack);
+#ifdef CONFIG_SMP
+ OFFSET(TI_CPU, task_struct, cpu);
+#endif
#ifdef CONFIG_LIVEPATCH
OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
@@ -164,8 +169,6 @@ int main(void)
OFFSET(TI_FLAGS, thread_info, flags);
OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
OFFSET(TI_PREEMPT, thread_info, preempt_count);
- OFFSET(TI_TASK, thread_info, task);
- OFFSET(TI_CPU, thread_info, cpu);
#ifdef CONFIG_PPC64
OFFSET(DCACHEL1BLOCKSIZE, ppc64_caches, l1d.block_size);
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 063100df8325..f3618353c1c4 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -1165,10 +1165,6 @@ ret_from_debug_exc:
mfspr r9,SPRN_SPRG_THREAD
lwz r10,SAVED_KSP_LIMIT(r1)
stw r10,KSP_LIMIT(r9)
- lwz r9,TASK_STACK-THREAD(r9)
- CURRENT_THREAD_INFO(r10, r1)
- lwz r10,TI_PREEMPT(r10)
- stw r10,TI_PREEMPT(r9)
RESTORE_xSRR(SRR0,SRR1);
RESTORE_xSRR(CSRR0,CSRR1);
RESTORE_MMU_REGS;
@@ -1291,10 +1287,13 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_601)
lwz r3,_TRAP(r1)
andi. r0,r3,1
- beq 4f
+ beq 5f
SAVE_NVGPRS(r1)
rlwinm r3,r3,0,0,30
stw r3,_TRAP(r1)
+5: mfspr r2,SPRN_SPRG_THREAD
+ addi r2,r2,-THREAD
+ tovirt(r2,r2) /* set back r2 to current */
4: addi r3,r1,STACK_FRAME_OVERHEAD
bl unrecoverable_exception
/* shouldn't return */
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index afb638778f44..20f14996281d 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -77,17 +77,6 @@ special_reg_save:
andi. r3,r3,MSR_PR
bnelr
- /* Copy info into temporary exception thread info */
- ld r11,PACAKSAVE(r13)
- CURRENT_THREAD_INFO(r11, r11)
- CURRENT_THREAD_INFO(r12, r1)
- ld r10,TI_FLAGS(r11)
- std r10,TI_FLAGS(r12)
- ld r10,TI_PREEMPT(r11)
- std r10,TI_PREEMPT(r12)
- ld r10,TI_TASK(r11)
- std r10,TI_TASK(r12)
-
/*
* Advance to the next TLB exception frame for handler
* types that don't do it automatically.
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 2112805ef1d1..888fcff3f8cc 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -834,9 +834,9 @@ __secondary_start:
/* get current's stack and current */
lis r1,secondary_ti@ha
tophys(r1,r1)
- lwz r1,secondary_ti@l(r1)
- tophys(r2,r1)
- lwz r2,TI_TASK(r2)
+ lwz r2,secondary_ti@l(r1)
+ tophys(r1,r2)
+ lwz r1,TASK_STACK(r1)
/* stack */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index 4e8c8bf50413..f94a93b6c2f2 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -1021,8 +1021,8 @@ _GLOBAL(start_secondary_47x)
/* Get current's stack and current */
lis r1,secondary_ti@ha
- lwz r1,secondary_ti@l(r1)
- lwz r2,TI_TASK(r1)
+ lwz r2,secondary_ti@l(r1)
+ lwz r1,TASK_STACK(r2)
/* Current stack pointer */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 69e80e6d0d16..1b22a8dea399 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -155,13 +155,7 @@ END_BTB_FLUSH_SECTION
stw r10,GPR11(r11); \
b 2f; \
/* COMING FROM PRIV MODE */ \
-1: lwz r9,TI_FLAGS-EXC_LVL_FRAME_OVERHEAD(r11); \
- lwz r10,TI_PREEMPT-EXC_LVL_FRAME_OVERHEAD(r11); \
- stw r9,TI_FLAGS-EXC_LVL_FRAME_OVERHEAD(r8); \
- stw r10,TI_PREEMPT-EXC_LVL_FRAME_OVERHEAD(r8); \
- lwz r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r11); \
- stw r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r8); \
- mr r11,r8; \
+1: mr r11, r8; \
2: mfspr r8,SPRN_SPRG_RSCRATCH_##exc_level; \
stw r12,GPR12(r11); /* save various registers */\
mflr r10; \
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 6301bb24889a..11f38adbe020 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -719,8 +719,7 @@ finish_tlb_load:
/* Get the next_tlbcam_idx percpu var */
#ifdef CONFIG_SMP
- lwz r12, TASK_STACK-THREAD(r12)
- lwz r15, TI_CPU(r12)
+ lwz r15, TI_CPU-THREAD(r12)
lis r14, __per_cpu_offset@h
ori r14, r14, __per_cpu_offset@l
rlwinm r15, r15, 2, 0, 29
@@ -1093,8 +1092,8 @@ __secondary_start:
/* get current's stack and current */
lis r1,secondary_ti@ha
- lwz r1,secondary_ti@l(r1)
- lwz r2,TI_TASK(r1)
+ lwz r2,secondary_ti@l(r1)
+ lwz r1,TASK_STACK(r2)
/* stack */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
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)
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index e1865565f0ae..7dd55eb1259d 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -151,41 +151,13 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
return 1;
}
-static DEFINE_PER_CPU(struct thread_info, kgdb_thread_info);
static int kgdb_singlestep(struct pt_regs *regs)
{
- struct thread_info *thread_info, *exception_thread_info;
- struct thread_info *backup_current_thread_info =
- this_cpu_ptr(&kgdb_thread_info);
-
if (user_mode(regs))
return 0;
- /*
- * On Book E and perhaps other processors, singlestep is handled on
- * the critical exception stack. This causes current_thread_info()
- * to fail, since it it locates the thread_info by masking off
- * the low bits of the current stack pointer. We work around
- * this issue by copying the thread_info from the kernel stack
- * before calling kgdb_handle_exception, and copying it back
- * afterwards. On most processors the copy is avoided since
- * exception_thread_info == thread_info.
- */
- thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
- exception_thread_info = current_thread_info();
-
- if (thread_info != exception_thread_info) {
- /* Save the original current_thread_info. */
- memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info);
- memcpy(exception_thread_info, thread_info, sizeof *thread_info);
- }
-
kgdb_handle_exception(0, SIGTRAP, 0, regs);
- if (thread_info != exception_thread_info)
- /* Restore current_thread_info lastly. */
- memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
-
return 1;
}
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index a0f6f45005bd..75692c327ba0 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -317,10 +317,8 @@ void default_machine_kexec(struct kimage *image)
* We setup preempt_count to avoid using VMX in memcpy.
* XXX: the task struct will likely be invalid once we do the copy!
*/
- kexec_stack.thread_info.task = current_thread_info()->task;
- kexec_stack.thread_info.flags = 0;
- kexec_stack.thread_info.preempt_count = HARDIRQ_OFFSET;
- kexec_stack.thread_info.cpu = current_thread_info()->cpu;
+ current_thread_info()->flags = 0;
+ current_thread_info()->preempt_count = HARDIRQ_OFFSET;
/* We need a static PACA, too; copy this CPU's PACA over and switch to
* it. Also poison per_cpu_offset and NULL lppaca to catch anyone using
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index dc2aaaf75c87..fd07711035bd 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1634,7 +1634,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
struct thread_info *ti = task_thread_info(p);
- klp_init_thread_info(ti);
+ klp_init_thread_info(p);
/* Copy registers */
sp -= sizeof(struct pt_regs);
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 9a6a0859c1ef..e7534f306c8e 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -937,7 +937,7 @@ void __init setup_arch(char **cmdline_p)
/* Reserve large chunks of memory for use by CMA for KVM. */
kvm_cma_reserve();
- klp_init_thread_info(&init_thread_info);
+ klp_init_thread_info(&init_task);
init_mm.start_code = (unsigned long)_stext;
init_mm.end_code = (unsigned long) _etext;
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 080dd515d587..0912948a8ea6 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -690,24 +690,6 @@ void __init exc_lvl_early_init(void)
#endif
/*
- * Emergency stacks are used for a range of things, from asynchronous
- * NMIs (system reset, machine check) to synchronous, process context.
- * We set preempt_count to zero, even though that isn't necessarily correct. To
- * get the right value we'd need to copy it from the previous thread_info, but
- * doing that might fault causing more problems.
- * TODO: what to do with accounting?
- */
-static void emerg_stack_init_thread_info(struct thread_info *ti, int cpu)
-{
- ti->task = NULL;
- ti->cpu = cpu;
- ti->preempt_count = 0;
- ti->local_flags = 0;
- ti->flags = 0;
- klp_init_thread_info(ti);
-}
-
-/*
* Stack space used when we detect a bad kernel stack pointer, and
* early in SMP boots before relocation is enabled. Exclusive emergency
* stack for machine checks.
@@ -737,18 +719,15 @@ void __init emergency_stack_init(void)
struct thread_info *ti;
ti = alloc_stack(limit, i);
- emerg_stack_init_thread_info(ti, i);
paca_ptrs[i]->emergency_sp = (void *)ti + THREAD_SIZE;
#ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for NMI exception handling. */
ti = alloc_stack(limit, i);
- emerg_stack_init_thread_info(ti, i);
paca_ptrs[i]->nmi_emergency_sp = (void *)ti + THREAD_SIZE;
/* emergency stack for machine check exception handling. */
ti = alloc_stack(limit, i);
- emerg_stack_init_thread_info(ti, i);
paca_ptrs[i]->mc_emergency_sp = (void *)ti + THREAD_SIZE;
#endif
}
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 829ef5411b50..96c25a89e877 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -988,7 +988,7 @@ static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
paca_ptrs[cpu]->kstack = (unsigned long)task_stack_page(idle) +
THREAD_SIZE - STACK_FRAME_OVERHEAD;
#endif
- ti->cpu = cpu;
+ idle->cpu = cpu;
secondary_ti = current_set[cpu] = ti;
}