[PATCH 2/2] ARM: Move thread_info into task_struct

From: Keith Packard
Date: Thu Sep 02 2021 - 11:55:18 EST

This avoids many stack overflow attacks which modified the thread_info
structure by moving that into the task_struct as is done is almost all
other architectures.

The task_struct is now referenced by a per-cpu variable,
'current_task', allowing the current one on each cpu to be located
from both C and assembly.

This also involved removing the 'cpu' member from the thread_info
struct and using the one found in the task_struct instead. That is
mostly used in asm code, where it might reasonably be replaced with
the recent per-cpu 'cpu_number' variable.

Signed-off-by: Keith Packard <keithpac@xxxxxxxxxx>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/assembler.h | 63 ++++++++++++++++++++++++------
arch/arm/include/asm/current.h | 36 +++++++++++++++++
arch/arm/include/asm/smp.h | 1 +
arch/arm/include/asm/thread_info.h | 14 -------
arch/arm/include/asm/tls.h | 4 +-
arch/arm/include/asm/uaccess-asm.h | 6 +--
arch/arm/kernel/asm-offsets.c | 31 ++++++++-------
arch/arm/kernel/entry-armv.S | 45 ++++++++++-----------
arch/arm/kernel/entry-common.S | 20 +++++-----
arch/arm/kernel/entry-v7m.S | 12 +++---
arch/arm/kernel/iwmmxt.S | 14 +++----
arch/arm/kernel/process.c | 1 +
arch/arm/kernel/setup.c | 9 ++---
arch/arm/kernel/smp.c | 12 +++++-
arch/arm/lib/copy_from_user.S | 4 +-
arch/arm/lib/copy_to_user.S | 4 +-
arch/arm/mach-ep93xx/crunch-bits.S | 2 +-
arch/arm/vfp/entry.S | 4 +-
arch/arm/vfp/vfpmodule.c | 29 +++++++-------
20 files changed, 193 insertions(+), 119 deletions(-)
create mode 100644 arch/arm/include/asm/current.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 24804f11302d..1be16c7d7360 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -128,6 +128,7 @@ config ARM
select RTC_LIB
select SET_FS
select SYS_SUPPORTS_APM_EMULATION
+ select THREAD_INFO_IN_TASK
# Above selects are sorted alphabetically; please add new ones
# according to that. Thanks.
help
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index e2b1fd558bf3..7723beed5cd9 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -200,13 +200,54 @@
.endr

/*
- * Get current thread_info.
+ * Get per-CPU offset
+ * rd: Destination register
*/
- .macro get_thread_info, rd
- ARM( mov \rd, sp, lsr #THREAD_SIZE_ORDER + PAGE_SHIFT )
- THUMB( mov \rd, sp )
- THUMB( lsr \rd, \rd, #THREAD_SIZE_ORDER + PAGE_SHIFT )
- mov \rd, \rd, lsl #THREAD_SIZE_ORDER + PAGE_SHIFT
+ .macro this_cpu_offset rd:req
+ mrc p15, 0, \rd, c13, c0, 4
+ .endm
+
+/*
+ * Load a per-cpu variable
+ * @dst: Destination register to receive value
+ * @sym: The name of the per-cpu variable
+ * @tmp: scratch register
+ */
+ .macro ldr_this_cpu dst : req, sym : req, tmp : req
+ movw \dst, #:lower16:\sym
+ movt \dst, #:upper16:\sym
+ this_cpu_offset \tmp
+ ldr \dst, [\dst, \tmp]
+ .endm
+
+/*
+ * Store a value in a per-cpu variable
+ * @src: Source register with value
+ * @sym: The name of the per-cpu variable
+ * @t1: scratch register 1
+ * @t2: scratch register 2
+ */
+ .macro str_this_cpu src : req, sym : req, t1 : req, t2 : req
+ movw \t1, #:lower16:\sym
+ movt \t1, #:upper16:\sym
+ this_cpu_offset \t2
+ str \src, [\t1, \t2]
+ .endm
+
+/*
+ * Get current task_info
+ * @dst: Destination register to receive current task
+ * @tmp: scratch register
+ */
+ .macro get_current, dst : req, tmp : req
+ ldr_this_cpu \dst, current_task, \tmp
+ .endm
+
+/*
+ * Set current task info
+ */
+ .macro set_current_task rs : req, t1 : req, t2 : req
+ str_this_cpu \rs, current_task, \t1, \t2
.endm

/*
@@ -214,19 +255,19 @@
*/
#ifdef CONFIG_PREEMPT_COUNT
.macro inc_preempt_count, ti, tmp
- ldr \tmp, [\ti, #TI_PREEMPT] @ get preempt count
+ ldr \tmp, [\ti, #TSK_TI_PREEMPT] @ get preempt count
add \tmp, \tmp, #1 @ increment it
- str \tmp, [\ti, #TI_PREEMPT]
+ str \tmp, [\ti, #TSK_TI_PREEMPT]
.endm

.macro dec_preempt_count, ti, tmp
- ldr \tmp, [\ti, #TI_PREEMPT] @ get preempt count
+ ldr \tmp, [\ti, #TSK_TI_PREEMPT] @ get preempt count
sub \tmp, \tmp, #1 @ decrement it
- str \tmp, [\ti, #TI_PREEMPT]
+ str \tmp, [\ti, #TSK_TI_PREEMPT]
.endm

.macro dec_preempt_count_ti, ti, tmp
- get_thread_info \ti
+ get_task_info \ti, \tmp
dec_preempt_count \ti, \tmp
.endm
#else
diff --git a/arch/arm/include/asm/current.h b/arch/arm/include/asm/current.h
new file mode 100644
index 000000000000..b389c4c0005c
--- /dev/null
+++ b/arch/arm/include/asm/current.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2021 Keith Packard <keithp@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef _ASM_ARM_CURRENT_H
+#define _ASM_ARM_CURRENT_H
+
+#include <linux/compiler.h>
+#include <linux/thread_info.h>
+#include <asm/percpu.h>
+
+#ifndef __ASSEMBLY__
+struct task_struct;
+
+DECLARE_PER_CPU(struct task_struct *, current_task);
+
+static __always_inline struct task_struct *get_current(void)
+{
+ return raw_cpu_read(current_task);
+}
+
+#define current get_current()
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARM_CURRENT_H */
diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
index 3aca2c2089bc..02989d094fd8 100644
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -64,6 +64,7 @@ struct secondary_data {
};
unsigned long swapper_pg_dir;
void *stack;
+ unsigned int cpu;
};
extern struct secondary_data secondary_data;
extern void secondary_startup(void);
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 70d4cbc49ae1..995ca0bcb7b1 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -55,8 +55,6 @@ struct thread_info {
unsigned long flags; /* low level flags */
int preempt_count; /* 0 => preemptable, <0 => bug */
mm_segment_t addr_limit; /* address limit */
- struct task_struct *task; /* main task structure */
- __u32 cpu; /* cpu */
__u32 cpu_domain; /* cpu domain */
#ifdef CONFIG_STACKPROTECTOR_PER_TASK
unsigned long stack_canary;
@@ -77,23 +75,11 @@ struct thread_info {

#define INIT_THREAD_INFO(tsk) \
{ \
- .task = &tsk, \
.flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
}

-/*
- * how to get the thread information struct from C
- */
-static inline struct thread_info *current_thread_info(void) __attribute_const__;
-
-static inline struct thread_info *current_thread_info(void)
-{
- return (struct thread_info *)
- (current_stack_pointer & ~(THREAD_SIZE - 1));
-}
-
#define thread_saved_pc(tsk) \
((unsigned long)(task_thread_info(tsk)->cpu_context.pc))
#define thread_saved_sp(tsk) \
diff --git a/arch/arm/include/asm/tls.h b/arch/arm/include/asm/tls.h
index 5a66c3b13c92..309e870e70a3 100644
--- a/arch/arm/include/asm/tls.h
+++ b/arch/arm/include/asm/tls.h
@@ -14,7 +14,7 @@
mrc p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
mcr p15, 0, \tp, c13, c0, 3 @ set TLS register
mcr p15, 0, \tpuser, c13, c0, 2 @ and the user r/w register
- str \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
+ str \tmp2, [\base, #TSK_TI_TP_VALUE + 4] @ save it
.endm

.macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
@@ -26,7 +26,7 @@
mrcne p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
mcrne p15, 0, \tp, c13, c0, 3 @ yes, set TLS register
mcrne p15, 0, \tpuser, c13, c0, 2 @ set user r/w register
- strne \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
+ strne \tmp2, [\base, #TSK_TI_TP_VALUE + 4] @ save it
.endm

.macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h
index e6eb7a2aaf1e..1c79d851a396 100644
--- a/arch/arm/include/asm/uaccess-asm.h
+++ b/arch/arm/include/asm/uaccess-asm.h
@@ -84,9 +84,9 @@
* if \disable is set.
*/
.macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable
- ldr \tmp1, [\tsk, #TI_ADDR_LIMIT]
+ ldr \tmp1, [\tsk, #TSK_TI_ADDR_LIMIT]
ldr \tmp2, =TASK_SIZE
- str \tmp2, [\tsk, #TI_ADDR_LIMIT]
+ str \tmp2, [\tsk, #TSK_TI_ADDR_LIMIT]
DACR( mrc p15, 0, \tmp0, c3, c0, 0)
DACR( str \tmp0, [sp, #SVC_DACR])
str \tmp1, [sp, #SVC_ADDR_LIMIT]
@@ -108,7 +108,7 @@
.macro uaccess_exit, tsk, tmp0, tmp1
ldr \tmp1, [sp, #SVC_ADDR_LIMIT]
DACR( ldr \tmp0, [sp, #SVC_DACR])
- str \tmp1, [\tsk, #TI_ADDR_LIMIT]
+ str \tmp1, [\tsk, #TSK_TI_ADDR_LIMIT]
DACR( mcr p15, 0, \tmp0, c3, c0, 0)
.endm

diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 70993af22d80..9de799481fb2 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -41,33 +41,34 @@ int main(void)
DEFINE(TSK_STACK_CANARY, offsetof(struct task_struct, stack_canary));
#endif
BLANK();
- DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
- DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
- DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
- DEFINE(TI_TASK, offsetof(struct thread_info, task));
- DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
- DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain));
- DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context));
- DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp));
- DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value));
- DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate));
+ DEFINE(TSK_TI_FLAGS, offsetof(struct task_struct, thread_info.flags));
+ DEFINE(TSK_TI_PREEMPT, offsetof(struct task_struct, thread_info.preempt_count));
+ DEFINE(TSK_TI_ADDR_LIMIT, offsetof(struct task_struct, thread_info.addr_limit));
+ DEFINE(TSK_TI_CPU_DOMAIN, offsetof(struct task_struct, thread_info.cpu_domain));
+ DEFINE(TSK_TI_CPU_SAVE, offsetof(struct task_struct, thread_info.cpu_context));
+ DEFINE(TSK_TI_USED_CP, offsetof(struct task_struct, thread_info.used_cp));
+ DEFINE(TSK_TI_TP_VALUE, offsetof(struct task_struct, thread_info.tp_value));
+ DEFINE(TSK_TI_FPSTATE, offsetof(struct task_struct, thread_info.fpstate));
+#ifdef CONFIG_SMP
+ DEFINE(TSK_CPU, offsetof(struct task_struct, cpu));
+#endif
#ifdef CONFIG_VFP
- DEFINE(TI_VFPSTATE, offsetof(struct thread_info, vfpstate));
+ DEFINE(TSK_TI_VFPSTATE, offsetof(struct task_struct, thread_info.vfpstate));
#ifdef CONFIG_SMP
DEFINE(VFP_CPU, offsetof(union vfp_state, hard.cpu));
#endif
#endif
#ifdef CONFIG_ARM_THUMBEE
- DEFINE(TI_THUMBEE_STATE, offsetof(struct thread_info, thumbee_state));
+ DEFINE(TSK_TI_THUMBEE_STATE, offsetof(struct task_struct, thread_info.thumbee_state));
#endif
#ifdef CONFIG_IWMMXT
- DEFINE(TI_IWMMXT_STATE, offsetof(struct thread_info, fpstate.iwmmxt));
+ DEFINE(TSK_TI_IWMMXT_STATE, offsetof(struct task_struct, thread_info.fpstate.iwmmxt));
#endif
#ifdef CONFIG_CRUNCH
- DEFINE(TI_CRUNCH_STATE, offsetof(struct thread_info, crunchstate));
+ DEFINE(TSK_TI_CRUNCH_STATE, offsetof(struct task_struct, thread_info.crunchstate));
#endif
#ifdef CONFIG_STACKPROTECTOR_PER_TASK
- DEFINE(TI_STACK_CANARY, offsetof(struct thread_info, stack_canary));
+ DEFINE(TSK_TI_STACK_CANARY, offsetof(struct task_struct, thread_info.stack_canary));
#endif
DEFINE(THREAD_SZ_ORDER, THREAD_SIZE_ORDER);
BLANK();
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 0ea8529a4872..2196e4dd7877 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -179,7 +179,7 @@ ENDPROC(__und_invalid)
@
stmia r7, {r2 - r6}

- get_thread_info tsk
+ get_current tsk, r0
uaccess_entry tsk, r0, r1, r2, \uaccess

.if \trace
@@ -205,8 +205,8 @@ __irq_svc:
irq_handler

#ifdef CONFIG_PREEMPTION
- ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
- ldr r0, [tsk, #TI_FLAGS] @ get flags
+ ldr r8, [tsk, #TSK_TI_PREEMPT] @ get preempt count
+ ldr r0, [tsk, #TSK_TI_FLAGS] @ get flags
teq r8, #0 @ if preempt count != 0
movne r0, #0 @ force flags to 0
tst r0, #_TIF_NEED_RESCHED
@@ -223,7 +223,7 @@ ENDPROC(__irq_svc)
svc_preempt:
mov r8, lr
1: bl preempt_schedule_irq @ irq en/disable is done inside
- ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
+ ldr r0, [tsk, #TSK_TI_FLAGS] @ get new tasks TI_FLAGS
tst r0, #_TIF_NEED_RESCHED
reteq r8 @ go again
b 1b
@@ -260,7 +260,7 @@ __und_svc:
bl __und_fault

__und_svc_finish:
- get_thread_info tsk
+ get_current tsk, r5
ldr r5, [sp, #S_PSR] @ Get SVC cpsr
svc_exit r5 @ return from exception
UNWIND(.fnend )
@@ -428,7 +428,7 @@ __irq_usr:
usr_entry
kuser_cmpxchg_check
irq_handler
- get_thread_info tsk
+ get_current tsk, why
mov why, #0
b ret_to_user_from_irq
UNWIND(.fnend )
@@ -572,12 +572,12 @@ ENDPROC(__und_usr)
@ Fall-through from Thumb-2 __und_usr
@
#ifdef CONFIG_NEON
- get_thread_info r10 @ get current thread
+ get_current r10, r6 @ get current thread
adr r6, .LCneon_thumb_opcodes
b 2f
#endif
call_fpe:
- get_thread_info r10 @ get current thread
+ get_current r10, r6 @ get current thread
#ifdef CONFIG_NEON
adr r6, .LCneon_arm_opcodes
2: ldr r5, [r6], #4 @ mask value
@@ -588,8 +588,8 @@ call_fpe:
cmp r8, r7 @ NEON instruction?
bne 2b
mov r7, #1
- strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
- strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
+ strb r7, [r10, #TSK_TI_USED_CP + 10] @ mark CP#10 as used
+ strb r7, [r10, #TSK_TI_USED_CP + 11] @ mark CP#11 as used
b do_vfp @ let VFP handler handle this
1:
#endif
@@ -599,12 +599,12 @@ call_fpe:
and r8, r0, #0x00000f00 @ mask out CP number
THUMB( lsr r8, r8, #8 )
mov r7, #1
- add r6, r10, #TI_USED_CP
+ add r6, r10, #TSK_TI_USED_CP
ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[]
THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[]
#ifdef CONFIG_IWMMXT
@ Test if we need to give access to iWMMXt coprocessors
- ldr r5, [r10, #TI_FLAGS]
+ ldr r5, [r10, #TSK_TI_FLAGS]
rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only
movscs r7, r5, lsr #(TIF_USING_IWMMXT + 1)
bcs iwmmxt_task_enable
@@ -674,7 +674,7 @@ call_fpe:

do_fpe:
ldr r4, .LCfp
- add r10, r10, #TI_FPSTATE @ r10 = workspace
+ add r10, r10, #TSK_TI_FPSTATE @ r10 = workspace
ldr pc, [r4] @ Call FP module USR entry point

/*
@@ -722,7 +722,7 @@ __pabt_usr:
ENTRY(ret_from_exception)
UNWIND(.fnstart )
UNWIND(.cantunwind )
- get_thread_info tsk
+ get_current tsk, why
mov why, #0
b ret_to_user
UNWIND(.fnend )
@@ -735,7 +735,7 @@ __fiq_usr:
kuser_cmpxchg_check
mov r0, sp @ struct pt_regs *regs
bl handle_fiq_as_nmi
- get_thread_info tsk
+ get_current tsk, r0
restore_user_regs fast = 0, offset = 0
UNWIND(.fnend )
ENDPROC(__fiq_usr)
@@ -748,21 +748,21 @@ ENDPROC(__fiq_usr)
ENTRY(__switch_to)
UNWIND(.fnstart )
UNWIND(.cantunwind )
- add ip, r1, #TI_CPU_SAVE
+ add ip, r1, #TSK_TI_CPU_SAVE
ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack
THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack
THUMB( str sp, [ip], #4 )
THUMB( str lr, [ip], #4 )
- ldr r4, [r2, #TI_TP_VALUE]
- ldr r5, [r2, #TI_TP_VALUE + 4]
+ ldr r4, [r2, #TSK_TI_TP_VALUE]
+ ldr r5, [r2, #TSK_TI_TP_VALUE + 4]
#ifdef CONFIG_CPU_USE_DOMAINS
mrc p15, 0, r6, c3, c0, 0 @ Get domain register
- str r6, [r1, #TI_CPU_DOMAIN] @ Save old domain register
- ldr r6, [r2, #TI_CPU_DOMAIN]
+ str r6, [r1, #TSK_TI_CPU_DOMAIN] @ Save old domain register
+ ldr r6, [r2, #TSK_TI_CPU_DOMAIN]
#endif
switch_tls r1, r4, r5, r3, r7
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
- ldr r7, [r2, #TI_TASK]
+ ldr r7, [r2, #TSK_TI_TASK]
ldr r8, =__stack_chk_guard
.if (TSK_STACK_CANARY > IMM12_MASK)
add r7, r7, #TSK_STACK_CANARY & ~IMM12_MASK
@@ -772,8 +772,9 @@ ENTRY(__switch_to)
#ifdef CONFIG_CPU_USE_DOMAINS
mcr p15, 0, r6, c3, c0, 0 @ Set domain register
#endif
+ set_current_task r2, r4, r5
mov r5, r0
- add r4, r2, #TI_CPU_SAVE
+ add r4, r2, #TSK_TI_CPU_SAVE
ldr r0, =thread_notify_head
mov r1, #THREAD_NOTIFY_SWITCH
bl atomic_notifier_call_chain
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 7f0b7aba1498..7a5044dbfc24 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -49,11 +49,11 @@ __ret_fast_syscall:
UNWIND(.fnstart )
UNWIND(.cantunwind )
disable_irq_notrace @ disable interrupts
- ldr r2, [tsk, #TI_ADDR_LIMIT]
+ ldr r2, [tsk, #TSK_TI_ADDR_LIMIT]
ldr r1, =TASK_SIZE
cmp r2, r1
blne addr_limit_check_failed
- ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
+ ldr r1, [tsk, #TSK_TI_FLAGS] @ re-check for syscall tracing
movs r1, r1, lsl #16
bne fast_work_pending

@@ -87,11 +87,11 @@ __ret_fast_syscall:
bl do_rseq_syscall
#endif
disable_irq_notrace @ disable interrupts
- ldr r2, [tsk, #TI_ADDR_LIMIT]
+ ldr r2, [tsk, #TSK_TI_ADDR_LIMIT]
ldr r1, =TASK_SIZE
cmp r2, r1
blne addr_limit_check_failed
- ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
+ ldr r1, [tsk, #TSK_TI_FLAGS] @ re-check for syscall tracing
movs r1, r1, lsl #16
beq no_work_pending
UNWIND(.fnend )
@@ -129,11 +129,11 @@ ret_slow_syscall:
#endif
disable_irq_notrace @ disable interrupts
ENTRY(ret_to_user_from_irq)
- ldr r2, [tsk, #TI_ADDR_LIMIT]
+ ldr r2, [tsk, #TSK_TI_ADDR_LIMIT]
ldr r1, =TASK_SIZE
cmp r2, r1
blne addr_limit_check_failed
- ldr r1, [tsk, #TI_FLAGS]
+ ldr r1, [tsk, #TSK_TI_FLAGS]
movs r1, r1, lsl #16
bne slow_work_pending
no_work_pending:
@@ -156,7 +156,7 @@ ENTRY(ret_from_fork)
movne r0, r4
badrne lr, 1f
retne r5
-1: get_thread_info tsk
+1: get_current tsk, r1
b ret_slow_syscall
ENDPROC(ret_from_fork)

@@ -243,7 +243,7 @@ ENTRY(vector_swi)
bic scno, scno, #0xff000000 @ mask off SWI op-code
eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
#endif
- get_thread_info tsk
+ get_current tsk, r10
/*
* Reload the registers that may have been corrupted on entry to
* the syscall assembly (by tracing or context tracking.)
@@ -251,7 +251,7 @@ ENTRY(vector_swi)
TRACE( ldmia sp, {r0 - r3} )

local_restart:
- ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
+ ldr r10, [tsk, #TSK_TI_FLAGS] @ check for syscall tracing
stmdb sp!, {r4, r5} @ push fifth and sixth args

tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
@@ -278,7 +278,7 @@ local_restart:
9001:
sub lr, saved_pc, #4
str lr, [sp, #S_PC]
- get_thread_info tsk
+ get_current tsk, r1
b ret_fast_syscall
#endif
ENDPROC(vector_swi)
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
index d0e898608d30..4de5ee2a432d 100644
--- a/arch/arm/kernel/entry-v7m.S
+++ b/arch/arm/kernel/entry-v7m.S
@@ -57,8 +57,8 @@ __irq_entry:
tst r0, V7M_SCB_ICSR_RETTOBASE
beq 2f

- get_thread_info tsk
- ldr r2, [tsk, #TI_FLAGS]
+ get_current tsk, r2
+ ldr r2, [tsk, #TSK_TI_FLAGS]
movs r2, r2, lsl #16
beq 2f @ no work pending
mov r0, #V7M_SCB_ICSR_PENDSVSET
@@ -83,7 +83,7 @@ __pendsv_entry:
str r0, [r1, V7M_SCB_ICSR] @ clear PendSV

@ execute the pending work, including reschedule
- get_thread_info tsk
+ get_current tsk, why
mov why, #0
b ret_to_user_from_irq
ENDPROC(__pendsv_entry)
@@ -96,17 +96,19 @@ ENDPROC(__pendsv_entry)
ENTRY(__switch_to)
.fnstart
.cantunwind
- add ip, r1, #TI_CPU_SAVE
+ add ip, r1, #TSK_TI_CPU_SAVE
stmia ip!, {r4 - r11} @ Store most regs on stack
str sp, [ip], #4
str lr, [ip], #4
mov r5, r0
- add r4, r2, #TI_CPU_SAVE
+ add r4, r2, #TSK_TI_CPU_SAVE
ldr r0, =thread_notify_head
mov r1, #THREAD_NOTIFY_SWITCH
bl atomic_notifier_call_chain
mov ip, r4
mov r0, r5
+ ldr r7, [r2, #TSK_TI_TASK]
+ set_current_task r7, r4, r5
ldmia ip!, {r4 - r11} @ Load all regs saved previously
ldr sp, [ip]
ldr pc, [ip, #4]!
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
index d2b4ac06e4ed..f709914b9029 100644
--- a/arch/arm/kernel/iwmmxt.S
+++ b/arch/arm/kernel/iwmmxt.S
@@ -84,7 +84,7 @@ ENTRY(iwmmxt_task_enable)
PJ4(mcr p15, 0, r2, c1, c0, 2)

ldr r3, =concan_owner
- add r0, r10, #TI_IWMMXT_STATE @ get task Concan save area
+ add r0, r10, #TSK_TI_IWMMXT_STATE @ get task Concan save area
ldr r2, [sp, #60] @ current task pc value
ldr r1, [r3] @ get current Concan owner
str r0, [r3] @ this task now owns Concan regs
@@ -96,7 +96,7 @@ ENTRY(iwmmxt_task_enable)
bl concan_save

#ifdef CONFIG_PREEMPT_COUNT
- get_thread_info r10
+ get_current r10, r3
#endif
4: dec_preempt_count r10, r3
ret r9 @ normal exit from exception
@@ -199,7 +199,7 @@ ENTRY(iwmmxt_task_disable)
msr cpsr_c, r2

ldr r3, =concan_owner
- add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
+ add r2, r0, #TSK_TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
teq r1, #0 @ any current owner?
beq 1f @ no: quit
@@ -251,7 +251,7 @@ ENTRY(iwmmxt_task_copy)
msr cpsr_c, r2

ldr r3, =concan_owner
- add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
+ add r2, r0, #TSK_TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
teq r2, r3 @ does this task own it...
beq 1f
@@ -289,7 +289,7 @@ ENTRY(iwmmxt_task_restore)
msr cpsr_c, r2

ldr r3, =concan_owner
- add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
+ add r2, r0, #TSK_TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
bic r2, r2, #0x7 @ 64-bit alignment
teq r2, r3 @ does this task own it...
@@ -328,7 +328,7 @@ ENTRY(iwmmxt_task_switch)
bne 1f @ yes: block them for next task

ldr r2, =concan_owner
- add r3, r0, #TI_IWMMXT_STATE @ get next task Concan save area
+ add r3, r0, #TSK_TI_IWMMXT_STATE @ get next task Concan save area
ldr r2, [r2] @ get current Concan owner
teq r2, r3 @ next task owns it?
retne lr @ no: leave Concan disabled
@@ -355,7 +355,7 @@ ENTRY(iwmmxt_task_release)
orr ip, r2, #PSR_I_BIT @ disable interrupts
msr cpsr_c, ip
ldr r3, =concan_owner
- add r0, r0, #TI_IWMMXT_STATE @ get task Concan save area
+ add r0, r0, #TSK_TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
eors r0, r0, r1 @ if equal...
streq r0, [r3] @ then clear ownership
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 6324f4db9b02..c7539f319f96 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -27,6 +27,7 @@
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <linux/leds.h>
+#include <linux/percpu.h>

#include <asm/processor.h>
#include <asm/thread_notify.h>
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 73ca7797b92f..a5a52817948a 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -532,12 +532,6 @@ void notrace cpu_init(void)
BUG();
}

- /*
- * This only works on resume and secondary cores. For booting on the
- * boot cpu, smp_prepare_boot_cpu is called after percpu area setup.
- */
- set_my_cpu_offset(per_cpu_offset(cpu));
-
cpu_proc_init();

/*
@@ -733,6 +727,9 @@ static void __init setup_processor(void)
elf_hwcap_fixup();

cacheid_init();
+
+ set_my_cpu_offset(per_cpu_offset(0));
+
cpu_init();
}

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 0457e25109c6..9b584811baad 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -51,6 +51,10 @@
#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>

+DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
+ &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
+
DEFINE_PER_CPU_READ_MOSTLY(unsigned int, cpu_number);
EXPORT_PER_CPU_SYMBOL(cpu_number);

@@ -156,8 +160,11 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
secondary_data.pgdir = virt_to_phys(idmap_pgd);
secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
#endif
+ secondary_data.cpu = cpu;
sync_cache_w(&secondary_data);

+ per_cpu(current_task, cpu) = idle;
+
/*
* Now bring the CPU into our world.
*/
@@ -406,7 +413,9 @@ static void smp_store_cpu_info(unsigned int cpuid)
asmlinkage void secondary_start_kernel(void)
{
struct mm_struct *mm = &init_mm;
- unsigned int cpu;
+ unsigned int cpu = secondary_data.cpu;
+
+ set_my_cpu_offset(per_cpu_offset(cpu));

secondary_biglittle_init();

@@ -423,7 +432,6 @@ asmlinkage void secondary_start_kernel(void)
* All kernel threads share the same mm context; grab a
* reference and switch to it.
*/
- cpu = smp_processor_id();
mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/arm/lib/copy_from_user.S b/arch/arm/lib/copy_from_user.S
index f8016e3db65d..4ed04f91ed0d 100644
--- a/arch/arm/lib/copy_from_user.S
+++ b/arch/arm/lib/copy_from_user.S
@@ -109,8 +109,8 @@

ENTRY(arm_copy_from_user)
#ifdef CONFIG_CPU_SPECTRE
- get_thread_info r3
- ldr r3, [r3, #TI_ADDR_LIMIT]
+ get_current r3, ip
+ ldr r3, [r3, #TSK_TI_ADDR_LIMIT]
uaccess_mask_range_ptr r1, r2, r3, ip
#endif

diff --git a/arch/arm/lib/copy_to_user.S b/arch/arm/lib/copy_to_user.S
index ebfe4cb3d912..229061cfb5b0 100644
--- a/arch/arm/lib/copy_to_user.S
+++ b/arch/arm/lib/copy_to_user.S
@@ -109,8 +109,8 @@
ENTRY(__copy_to_user_std)
WEAK(arm_copy_to_user)
#ifdef CONFIG_CPU_SPECTRE
- get_thread_info r3
- ldr r3, [r3, #TI_ADDR_LIMIT]
+ get_current r3, ip
+ ldr r3, [r3, #TSK_TI_ADDR_LIMIT]
uaccess_mask_range_ptr r0, r2, r3, ip
#endif

diff --git a/arch/arm/mach-ep93xx/crunch-bits.S b/arch/arm/mach-ep93xx/crunch-bits.S
index fb2dbf76f09e..dad62e3d4b03 100644
--- a/arch/arm/mach-ep93xx/crunch-bits.S
+++ b/arch/arm/mach-ep93xx/crunch-bits.S
@@ -192,7 +192,7 @@ crunch_load:

1:
#ifdef CONFIG_PREEMPT_COUNT
- get_thread_info r10
+ get_task_info r10, r3
#endif
2: dec_preempt_count r10, r3
ret lr
diff --git a/arch/arm/vfp/entry.S b/arch/arm/vfp/entry.S
index 27b0a1f27fbd..003554f8393d 100644
--- a/arch/arm/vfp/entry.S
+++ b/arch/arm/vfp/entry.S
@@ -24,8 +24,8 @@
ENTRY(do_vfp)
inc_preempt_count r10, r4
ldr r4, .LCvfp
- ldr r11, [r10, #TI_CPU] @ CPU number
- add r10, r10, #TI_VFPSTATE @ r10 = workspace
+ ldr r11, [r10, #TSK_CPU] @ CPU number
+ add r10, r10, #TSK_TI_VFPSTATE @ r10 = workspace
ldr pc, [r4] @ call VFP entry point
ENDPROC(do_vfp)

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 2cb355c1b5b7..4e2707fba8fd 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -143,22 +143,22 @@ static void vfp_thread_copy(struct thread_info *thread)
* THREAD_NOFTIFY_SWTICH:
* - the previously running thread will not be scheduled onto another CPU.
* - the next thread to be run (v) will not be running on another CPU.
- * - thread->cpu is the local CPU number
+ * - tsk->cpu is the local CPU number
* - not preemptible as we're called in the middle of a thread switch
* THREAD_NOTIFY_FLUSH:
* - the thread (v) will be running on the local CPU, so
- * v === current_thread_info()
- * - thread->cpu is the local CPU number at the time it is accessed,
+ * v === current
+ * - tsk->cpu is the local CPU number at the time it is accessed,
* but may change at any time.
* - we could be preempted if tree preempt rcu is enabled, so
- * it is unsafe to use thread->cpu.
+ * it is unsafe to use tsk->cpu.
* THREAD_NOTIFY_EXIT
* - we could be preempted if tree preempt rcu is enabled, so
- * it is unsafe to use thread->cpu.
+ * it is unsafe to use tsk->cpu.
*/
static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
{
- struct thread_info *thread = v;
+ struct task_struct *tsk = v;
u32 fpexc;
#ifdef CONFIG_SMP
unsigned int cpu;
@@ -169,7 +169,7 @@ static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
fpexc = fmrx(FPEXC);

#ifdef CONFIG_SMP
- cpu = thread->cpu;
+ cpu = tsk->cpu;

/*
* On SMP, if VFP is enabled, save the old state in
@@ -188,15 +188,15 @@ static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
break;

case THREAD_NOTIFY_FLUSH:
- vfp_thread_flush(thread);
+ vfp_thread_flush(&tsk->thread_info);
break;

case THREAD_NOTIFY_EXIT:
- vfp_thread_exit(thread);
+ vfp_thread_exit(&tsk->thread_info);
break;

case THREAD_NOTIFY_COPY:
- vfp_thread_copy(thread);
+ vfp_thread_copy(&tsk->thread_info);
break;
}

@@ -448,26 +448,25 @@ void __init vfp_disable(void)
#ifdef CONFIG_CPU_PM
static int vfp_pm_suspend(void)
{
- struct thread_info *ti = current_thread_info();
u32 fpexc = fmrx(FPEXC);

/* if vfp is on, then save state for resumption */
if (fpexc & FPEXC_EN) {
pr_debug("%s: saving vfp state\n", __func__);
- vfp_save_state(&ti->vfpstate, fpexc);
+ vfp_save_state(&current->thread_info.vfpstate, fpexc);

/* disable, just in case */
fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
- } else if (vfp_current_hw_state[ti->cpu]) {
+ } else if (vfp_current_hw_state[current->cpu]) {
#ifndef CONFIG_SMP
fmxr(FPEXC, fpexc | FPEXC_EN);
- vfp_save_state(vfp_current_hw_state[ti->cpu], fpexc);
+ vfp_save_state(vfp_current_hw_state[current->cpu], fpexc);
fmxr(FPEXC, fpexc);
#endif
}

/* clear any information we had about last context state */
- vfp_current_hw_state[ti->cpu] = NULL;
+ vfp_current_hw_state[current->cpu] = NULL;

return 0;
}
--
2.33.0