[PATCH v15 07/13] powerpc: Prepare for moving thread_info into task_struct

From: Christophe Leroy
Date: Thu Jan 31 2019 - 05:09:03 EST

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This patch cleans the powerpc kernel before activating
CONFIG_THREAD_INFO_IN_TASK:
- The purpose of the pointer given to call_do_softirq() and
call_do_irq() is to point the new stack ==> change it to void* and
rename it 'sp'
- Don't use CURRENT_THREAD_INFO() to locate the stack.
- Fix a few comments.
- Replace current_thread_info()->task by current
- Makes TASK_STACK available to PPC64. PPC64 will need it to get the
stack pointer from current once the thread_info have been moved.
- In idle_6xx.S, make sure CURRENT_THREAD_INFO() is used with r1
which is the virtual address of the stack, in order to ease the switch
to r2 as we have no register having the phys address of current.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
Reviewed-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/include/asm/irq.h | 4 ++--
arch/powerpc/include/asm/processor.h | 4 ++--
arch/powerpc/include/asm/reg.h | 2 +-
arch/powerpc/kernel/asm-offsets.c | 2 +-
arch/powerpc/kernel/entry_64.S | 2 +-
arch/powerpc/kernel/head_32.S | 2 +-
arch/powerpc/kernel/head_44x.S | 2 +-
arch/powerpc/kernel/head_fsl_booke.S | 2 +-
arch/powerpc/kernel/idle_6xx.S | 3 ++-
arch/powerpc/kernel/irq.c | 2 +-
arch/powerpc/kernel/misc_32.S | 4 ++--
arch/powerpc/kernel/process.c | 6 +++---
arch/powerpc/kernel/smp.c | 4 +++-
13 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index ee39ce56b2a2..2efbae8d93be 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -63,8 +63,8 @@ extern struct thread_info *hardirq_ctx[NR_CPUS];
extern struct thread_info *softirq_ctx[NR_CPUS];

extern void irq_ctx_init(void);
-extern void call_do_softirq(struct thread_info *tp);
-extern void call_do_irq(struct pt_regs *regs, struct thread_info *tp);
+void call_do_softirq(void *sp);
+void call_do_irq(struct pt_regs *regs, void *sp);
extern void do_IRQ(struct pt_regs *regs);
extern void __init init_IRQ(void);
extern void __do_irq(struct pt_regs *regs);
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 692f7383d461..15acb282a876 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -40,7 +40,7 @@

#ifndef __ASSEMBLY__
#include <linux/types.h>
-#include <asm/thread_info.h>
+#include <linux/thread_info.h>
#include <asm/ptrace.h>
#include <asm/hw_breakpoint.h>

@@ -326,7 +326,7 @@ struct thread_struct {

#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
#define INIT_SP_LIMIT \
- (_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
+ (_ALIGN_UP(sizeof(struct thread_info), 16) + (unsigned long)&init_stack)

#ifdef CONFIG_SPE
#define SPEFSCR_INIT \
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1c98ef1f2d5b..581e61db2dcf 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1062,7 +1062,7 @@
* - SPRG9 debug exception scratch
*
* All 32-bit:
- * - SPRG3 current thread_info pointer
+ * - SPRG3 current thread_struct physical addr pointer
* (virtual on BookE, physical on others)
*
* 32-bit classic:
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 23456ba3410a..b2b52e002a76 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -90,10 +90,10 @@ int main(void)
DEFINE(SIGSEGV, SIGSEGV);
DEFINE(NMI_MASK, NMI_MASK);
#else
- OFFSET(TASK_STACK, task_struct, stack);
DEFINE(THREAD_INFO_GAP, _ALIGN_UP(sizeof(struct thread_info), 16));
OFFSET(KSP_LIMIT, thread_struct, ksp_limit);
#endif /* CONFIG_PPC64 */
+ OFFSET(TASK_STACK, task_struct, stack);

#ifdef CONFIG_LIVEPATCH
OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 435927f549c4..01d0706d873f 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -695,7 +695,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
2:
#endif /* CONFIG_PPC_BOOK3S_64 */

- CURRENT_THREAD_INFO(r7, r8) /* base of new stack */
+ clrrdi r7, r8, THREAD_SHIFT /* base of new stack */
/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
because we don't need to leave the 288-byte ABI gap at the
top of the kernel stack. */
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 9268e5e87949..8282d25948ae 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -845,7 +845,7 @@ __secondary_start:
bl init_idle_6xx
#endif /* CONFIG_PPC_BOOK3S_32 */

- /* get current_thread_info and current */
+ /* get current's stack and current */
lis r1,secondary_ti@ha
tophys(r1,r1)
lwz r1,secondary_ti@l(r1)
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index bf23c19c92d6..4e8c8bf50413 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -1019,7 +1019,7 @@ _GLOBAL(start_secondary_47x)

/* Now we can get our task struct and real stack pointer */

- /* Get current_thread_info and current */
+ /* Get current's stack and current */
lis r1,secondary_ti@ha
lwz r1,secondary_ti@l(r1)
lwz r2,TI_TASK(r1)
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 42d8d6fc00cb..6301bb24889a 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -1091,7 +1091,7 @@ __secondary_start:
mr r4,r24 /* Why? */
bl call_setup_cpu

- /* get current_thread_info and current */
+ /* get current's stack and current */
lis r1,secondary_ti@ha
lwz r1,secondary_ti@l(r1)
lwz r2,TI_TASK(r1)
diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index ff026c9d3cab..d9b6e7e0b5e3 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -159,7 +159,8 @@ _GLOBAL(power_save_ppc32_restore)
stw r9,_NIP(r11) /* make it do a blr */

#ifdef CONFIG_SMP
- CURRENT_THREAD_INFO(r12, r11)
+ CURRENT_THREAD_INFO(r12, r1)
+ tophys(r12, r12)
lwz r11,TI_CPU(r12) /* get cpu number * 4 */
slwi r11,r11,2
#else
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 4a5dd8800946..531e9ef153c0 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -663,7 +663,7 @@ void do_IRQ(struct pt_regs *regs)
struct thread_info *curtp, *irqtp, *sirqtp;

/* Switch to the irq stack to handle this */
- curtp = current_thread_info();
+ curtp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
irqtp = hardirq_ctx[raw_smp_processor_id()];
sirqtp = softirq_ctx[raw_smp_processor_id()];

diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 02b8cdd73792..b37b50fde828 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -60,7 +60,7 @@ _GLOBAL(call_do_softirq)
blr

/*
- * void call_do_irq(struct pt_regs *regs, struct thread_info *irqtp);
+ * void call_do_irq(struct pt_regs *regs, void *sp);
*/
_GLOBAL(call_do_irq)
mflr r0
@@ -603,7 +603,7 @@ EXPORT_SYMBOL(__bswapdi2)
#ifdef CONFIG_SMP
_GLOBAL(start_secondary_resume)
/* Reset stack */
- CURRENT_THREAD_INFO(r1, r1)
+ rlwinm r1, r1, 0, 0, 31 - THREAD_SHIFT
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
li r3,0
stw r3,0(r1) /* Zero the stack frame pointer */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 4ffbb677c9f5..21c1e11a06de 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1231,8 +1231,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
batch->active = 1;
}

- if (current_thread_info()->task->thread.regs) {
- restore_math(current_thread_info()->task->thread.regs);
+ if (current->thread.regs) {
+ restore_math(current->thread.regs);

/*
* The copy-paste buffer can only store into foreign real
@@ -1242,7 +1242,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
* mappings, we must issue a cp_abort to clear any state and
* prevent snooping, corruption or a covert channel.
*/
- if (current_thread_info()->task->thread.used_vas)
+ if (current->thread.used_vas)
asm volatile(PPC_CP_ABORT);
}
#endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 3f15edf25a0d..1d3e7cb6704d 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -20,6 +20,7 @@
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched/mm.h>
+#include <linux/sched/task_stack.h>
#include <linux/sched/topology.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
@@ -1017,7 +1018,8 @@ static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)

#ifdef CONFIG_PPC64
paca_ptrs[cpu]->__current = idle;
- paca_ptrs[cpu]->kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
+ paca_ptrs[cpu]->kstack = (unsigned long)task_stack_page(idle) +
+ THREAD_SIZE - STACK_FRAME_OVERHEAD;
#endif
ti->cpu = cpu;
secondary_ti = current_set[cpu] = ti;
--
2.13.3

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