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Message-Id: <29f6c4b8e7a5bbc61e6a8801b78bbf493f9f819e.1597770847.git.christophe.leroy@csgroup.eu>
Date: Tue, 18 Aug 2020 17:19:35 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 23/25] powerpc/signal: Create 'unsafe' versions of
copy_[ck][fpr/vsx]_to_user()
For the non VSX version, that's trivial. Just use unsafe_copy_to_user()
instead of __copy_to_user().
For the VSX version, remove the intermediate step through a buffer and
use unsafe_put_user() directly. This generates a far smaller code which
is acceptable to inline, see below:
Standard VSX version:
0000000000000000 <.copy_fpr_to_user>:
0: 7c 08 02 a6 mflr r0
4: fb e1 ff f8 std r31,-8(r1)
8: 39 00 00 20 li r8,32
c: 39 24 0b 80 addi r9,r4,2944
10: 7d 09 03 a6 mtctr r8
14: f8 01 00 10 std r0,16(r1)
18: f8 21 fe 71 stdu r1,-400(r1)
1c: 39 41 00 68 addi r10,r1,104
20: e9 09 00 00 ld r8,0(r9)
24: 39 4a 00 08 addi r10,r10,8
28: 39 29 00 10 addi r9,r9,16
2c: f9 0a 00 00 std r8,0(r10)
30: 42 00 ff f0 bdnz 20 <.copy_fpr_to_user+0x20>
34: e9 24 0d 80 ld r9,3456(r4)
38: 3d 42 00 00 addis r10,r2,0
3a: R_PPC64_TOC16_HA .toc
3c: eb ea 00 00 ld r31,0(r10)
3e: R_PPC64_TOC16_LO_DS .toc
40: f9 21 01 70 std r9,368(r1)
44: e9 3f 00 00 ld r9,0(r31)
48: 81 29 00 20 lwz r9,32(r9)
4c: 2f 89 00 00 cmpwi cr7,r9,0
50: 40 9c 00 18 bge cr7,68 <.copy_fpr_to_user+0x68>
54: 4c 00 01 2c isync
58: 3d 20 40 00 lis r9,16384
5c: 79 29 07 c6 rldicr r9,r9,32,31
60: 7d 3d 03 a6 mtspr 29,r9
64: 4c 00 01 2c isync
68: 38 a0 01 08 li r5,264
6c: 38 81 00 70 addi r4,r1,112
70: 48 00 00 01 bl 70 <.copy_fpr_to_user+0x70>
70: R_PPC64_REL24 .__copy_tofrom_user
74: 60 00 00 00 nop
78: e9 3f 00 00 ld r9,0(r31)
7c: 81 29 00 20 lwz r9,32(r9)
80: 2f 89 00 00 cmpwi cr7,r9,0
84: 40 9c 00 18 bge cr7,9c <.copy_fpr_to_user+0x9c>
88: 4c 00 01 2c isync
8c: 39 20 ff ff li r9,-1
90: 79 29 00 44 rldicr r9,r9,0,1
94: 7d 3d 03 a6 mtspr 29,r9
98: 4c 00 01 2c isync
9c: 38 21 01 90 addi r1,r1,400
a0: e8 01 00 10 ld r0,16(r1)
a4: eb e1 ff f8 ld r31,-8(r1)
a8: 7c 08 03 a6 mtlr r0
ac: 4e 80 00 20 blr
'unsafe' simulated VSX version (The ... are only nops) using
unsafe_copy_fpr_to_user() macro:
unsigned long copy_fpr_to_user(void __user *to,
struct task_struct *task)
{
unsafe_copy_fpr_to_user(to, task, failed);
return 0;
failed:
return 1;
}
0000000000000000 <.copy_fpr_to_user>:
0: 39 00 00 20 li r8,32
4: 39 44 0b 80 addi r10,r4,2944
8: 7d 09 03 a6 mtctr r8
c: 7c 69 1b 78 mr r9,r3
...
20: e9 0a 00 00 ld r8,0(r10)
24: f9 09 00 00 std r8,0(r9)
28: 39 4a 00 10 addi r10,r10,16
2c: 39 29 00 08 addi r9,r9,8
30: 42 00 ff f0 bdnz 20 <.copy_fpr_to_user+0x20>
34: e9 24 0d 80 ld r9,3456(r4)
38: f9 23 01 00 std r9,256(r3)
3c: 38 60 00 00 li r3,0
40: 4e 80 00 20 blr
...
50: 38 60 00 01 li r3,1
54: 4e 80 00 20 blr
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/kernel/signal.h | 53 ++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
index f610cfafa478..2559a681536e 100644
--- a/arch/powerpc/kernel/signal.h
+++ b/arch/powerpc/kernel/signal.h
@@ -32,7 +32,54 @@ unsigned long copy_fpr_to_user(void __user *to, struct task_struct *task);
unsigned long copy_ckfpr_to_user(void __user *to, struct task_struct *task);
unsigned long copy_fpr_from_user(struct task_struct *task, void __user *from);
unsigned long copy_ckfpr_from_user(struct task_struct *task, void __user *from);
+
+#define unsafe_copy_fpr_to_user(to, task, label) do { \
+ struct task_struct *__t = task; \
+ u64 __user *buf = (u64 __user *)to; \
+ int i; \
+ \
+ for (i = 0; i < ELF_NFPREG - 1 ; i++) \
+ unsafe_put_user(__t->thread.TS_FPR(i), &buf[i], label); \
+ unsafe_put_user(__t->thread.fp_state.fpscr, &buf[i], label); \
+} while (0)
+
+#define unsafe_copy_vsx_to_user(to, task, label) do { \
+ struct task_struct *__t = task; \
+ u64 __user *buf = (u64 __user *)to; \
+ int i; \
+ \
+ for (i = 0; i < ELF_NVSRHALFREG ; i++) \
+ unsafe_put_user(__t->thread.fp_state.fpr[i][TS_VSRLOWOFFSET], \
+ &buf[i], label);\
+} while (0)
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+#define unsafe_copy_ckfpr_to_user(to, task, label) do { \
+ struct task_struct *__t = task; \
+ u64 __user *buf = (u64 __user *)to; \
+ int i; \
+ \
+ for (i = 0; i < ELF_NFPREG - 1 ; i++) \
+ unsafe_put_user(__t->thread.TS_CKFPR(i), &buf[i], label);\
+ unsafe_put_user(__t->thread.ckfp_state.fpscr, &buf[i], label); \
+} while (0)
+
+#define unsafe_copy_ckvsx_to_user(to, task, label) do { \
+ struct task_struct *__t = task; \
+ u64 __user *buf = (u64 __user *)to; \
+ int i; \
+ \
+ for (i = 0; i < ELF_NVSRHALFREG ; i++) \
+ unsafe_put_user(__t->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET], \
+ &buf[i], label);\
+} while (0)
+#endif
#elif defined(CONFIG_PPC_FPU_REGS)
+
+#define unsafe_copy_fpr_to_user(to, task, label) \
+ unsafe_copy_to_user(to, (task)->thread.fp_state.fpr, \
+ ELF_NFPREG * sizeof(double), label)
+
static inline unsigned long
copy_fpr_to_user(void __user *to, struct task_struct *task)
{
@@ -48,6 +95,10 @@ copy_fpr_from_user(struct task_struct *task, void __user *from)
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+#define unsafe_copy_ckfpr_to_user(to, task, label) \
+ unsafe_copy_to_user(to, (task)->thread.ckfp_state.fpr, \
+ ELF_NFPREG * sizeof(double), label)
+
inline unsigned long copy_ckfpr_to_user(void __user *to, struct task_struct *task)
{
return __copy_to_user(to, task->thread.ckfp_state.fpr,
@@ -62,6 +113,8 @@ copy_ckfpr_from_user(struct task_struct *task, void __user *from)
}
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
#else
+#define unsafe_copy_fpr_to_user(to, task, label) do { } while (0)
+
static inline unsigned long
copy_fpr_to_user(void __user *to, struct task_struct *task)
{
--
2.25.0
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