Commit c7e6f0e9 authored by Guo Ren's avatar Guo Ren
Browse files

csky: Support kernel non-aligned access 



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: default avatarGuo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
parent dc140045

arch/csky/abiv1/alignment.c

+45 −17
Original line number Diff line number Diff line
@@ -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 @@ bad_area: 
	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

	},

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