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Message-Id: <1566304469-5601-3-git-send-email-guoren@kernel.org>
Date: Tue, 20 Aug 2019 20:34:29 +0800
From: guoren@...nel.org
To: arnd@...db.de
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
linux-csky@...r.kernel.org, douzhk@...ionalchip.com,
Guo Ren <ren_guo@...ky.com>
Subject: [PATCH 3/3] csky: Support kernel non-aligned access
From: Guo Ren <ren_guo@...ky.com>
We prohibit non-aligned access in kernel mode, but some special NIC
driver needs to support kernel-state unaligned access. For example,
when the bus does not support unaligned access, IP header parsing
will cause non-aligned access and driver does not recopy the skb
buffer to dma for performance reasons.
Added kernel_enable & user_enable to control unaligned access and
added kernel_count & user_count for statistical unaligned access.
Signed-off-by: Guo Ren <ren_guo@...ky.com>
Cc: Arnd Bergmann <arnd@...db.de>
---
arch/csky/abiv1/alignment.c | 62 ++++++++++++++++++++++++++++++++-------------
1 file changed, 45 insertions(+), 17 deletions(-)
diff --git a/arch/csky/abiv1/alignment.c b/arch/csky/abiv1/alignment.c
index 27ef5b2..cb2a0d9 100644
--- a/arch/csky/abiv1/alignment.c
+++ b/arch/csky/abiv1/alignment.c
@@ -5,8 +5,10 @@
#include <linux/uaccess.h>
#include <linux/ptrace.h>
-static int align_enable = 1;
-static int align_count;
+static int align_kern_enable = 1;
+static int align_usr_enable = 1;
+static int align_kern_count = 0;
+static int align_usr_count = 0;
static inline uint32_t get_ptreg(struct pt_regs *regs, uint32_t rx)
{
@@ -32,9 +34,6 @@ static int ldb_asm(uint32_t addr, uint32_t *valp)
uint32_t val;
int err;
- if (!access_ok((void *)addr, 1))
- return 1;
-
asm volatile (
"movi %0, 0\n"
"1:\n"
@@ -67,9 +66,6 @@ static int stb_asm(uint32_t addr, uint32_t val)
{
int err;
- if (!access_ok((void *)addr, 1))
- return 1;
-
asm volatile (
"movi %0, 0\n"
"1:\n"
@@ -203,8 +199,6 @@ static int stw_c(struct pt_regs *regs, uint32_t rz, uint32_t addr)
if (stb_asm(addr, byte3))
return 1;
- align_count++;
-
return 0;
}
@@ -226,7 +220,14 @@ void csky_alignment(struct pt_regs *regs)
uint32_t addr = 0;
if (!user_mode(regs))
+ goto kernel_area;
+
+ if (!align_usr_enable) {
+ pr_err("%s user disabled.\n", __func__);
goto bad_area;
+ }
+
+ align_usr_count++;
ret = get_user(tmp, (uint16_t *)instruction_pointer(regs));
if (ret) {
@@ -234,6 +235,19 @@ void csky_alignment(struct pt_regs *regs)
goto bad_area;
}
+ goto good_area;
+
+kernel_area:
+ if (!align_kern_enable) {
+ pr_err("%s kernel disabled.\n", __func__);
+ goto bad_area;
+ }
+
+ align_kern_count++;
+
+ tmp = *(uint16_t *)instruction_pointer(regs);
+
+good_area:
opcode = (uint32_t)tmp;
rx = opcode & 0xf;
@@ -286,18 +300,32 @@ void csky_alignment(struct pt_regs *regs)
force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)addr);
}
-static struct ctl_table alignment_tbl[4] = {
+static struct ctl_table alignment_tbl[5] = {
+ {
+ .procname = "kernel_enable",
+ .data = &align_kern_enable,
+ .maxlen = sizeof(align_kern_enable),
+ .mode = 0666,
+ .proc_handler = &proc_dointvec
+ },
+ {
+ .procname = "user_enable",
+ .data = &align_usr_enable,
+ .maxlen = sizeof(align_usr_enable),
+ .mode = 0666,
+ .proc_handler = &proc_dointvec
+ },
{
- .procname = "enable",
- .data = &align_enable,
- .maxlen = sizeof(align_enable),
+ .procname = "kernel_count",
+ .data = &align_kern_count,
+ .maxlen = sizeof(align_kern_count),
.mode = 0666,
.proc_handler = &proc_dointvec
},
{
- .procname = "count",
- .data = &align_count,
- .maxlen = sizeof(align_count),
+ .procname = "user_count",
+ .data = &align_usr_count,
+ .maxlen = sizeof(align_usr_count),
.mode = 0666,
.proc_handler = &proc_dointvec
},
--
2.7.4
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