[PATCH 2/3] MIPS: uaccess: Remove get_fs/set_fs call sites

From: Thomas Bogendoerfer
Date: Tue Mar 30 2021 - 13:27:45 EST

Use new __get_data macro to access user/kernel for functions, which
are used with user/kernel pointers. Instead of dealing with get_fs/set_fs
this macro uses a parameter to select user/kernel access.

Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/uaccess.h | 23 ++++
arch/mips/kernel/traps.c | 72 ++++--------
arch/mips/kernel/unaligned.c | 197 ++++++++++++--------------------
3 files changed, 116 insertions(+), 176 deletions(-)

diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index c5cab0b8f902..8b3a4b992ebc 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -355,6 +355,29 @@ do { \
(val) = __gu_tmp.t; \
}

+#define __get_udata(x, ptr, size) \
+({ \
+ int __gu_err; \
+ \
+ __chk_user_ptr(ptr); \
+ __get_user_common((x), size, ptr); \
+ \
+ __gu_err; \
+})
+
+#define __get_kdata(x, ptr, size) \
+({ \
+ int __gu_err; \
+ \
+ __get_kernel_common((x), size, ptr); \
+ \
+ __gu_err; \
+})
+
+#define __get_data(x, ptr, u) \
+ (((u) == true) ? __get_udata((x), (ptr), sizeof(*(ptr))) : \
+ __get_kdata((x), (ptr), sizeof(*(ptr))))
+
#define HAVE_GET_KERNEL_NOFAULT

#define __get_kernel_nofault(dst, src, type, err_label) \
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 808b8b61ded1..6561c0c7841d 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -108,7 +108,8 @@ void (*board_bind_eic_interrupt)(int irq, int regset);
void (*board_ebase_setup)(void);
void(*board_cache_error_setup)(void);

-static void show_raw_backtrace(unsigned long reg29, const char *loglvl)
+static void show_raw_backtrace(unsigned long reg29, const char *loglvl,
+ bool user)
{
unsigned long *sp = (unsigned long *)(reg29 & ~3);
unsigned long addr;
@@ -120,7 +121,7 @@ static void show_raw_backtrace(unsigned long reg29, const char *loglvl)
while (!kstack_end(sp)) {
unsigned long __user *p =
(unsigned long __user *)(unsigned long)sp++;
- if (__get_user(addr, p)) {
+ if (__get_data(addr, p, user)) {
printk("%s (Bad stack address)", loglvl);
break;
}
@@ -141,7 +142,7 @@ __setup("raw_show_trace", set_raw_show_trace);
#endif

static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
- const char *loglvl)
+ const char *loglvl, bool user)
{
unsigned long sp = regs->regs[29];
unsigned long ra = regs->regs[31];
@@ -151,7 +152,7 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
task = current;

if (raw_show_trace || user_mode(regs) || !__kernel_text_address(pc)) {
- show_raw_backtrace(sp, loglvl);
+ show_raw_backtrace(sp, loglvl, user);
return;
}
printk("%sCall Trace:\n", loglvl);
@@ -167,7 +168,7 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
* with at least a bit of error checking ...
*/
static void show_stacktrace(struct task_struct *task,
- const struct pt_regs *regs, const char *loglvl)
+ const struct pt_regs *regs, const char *loglvl, bool user)
{
const int field = 2 * sizeof(unsigned long);
long stackdata;
@@ -186,7 +187,7 @@ static void show_stacktrace(struct task_struct *task,
break;
}

- if (__get_user(stackdata, sp++)) {
+ if (__get_data(stackdata, sp++, user)) {
pr_cont(" (Bad stack address)");
break;
}
@@ -195,13 +196,12 @@ static void show_stacktrace(struct task_struct *task,
i++;
}
pr_cont("\n");
- show_backtrace(task, regs, loglvl);
+ show_backtrace(task, regs, loglvl, user);
}

void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
{
struct pt_regs regs;
- mm_segment_t old_fs = get_fs();

regs.cp0_status = KSU_KERNEL;
if (sp) {
@@ -217,16 +217,10 @@ void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
prepare_frametrace(&regs);
}
}
- /*
- * show_stack() deals exclusively with kernel mode, so be sure to access
- * the stack in the kernel (not user) address space.
- */
- set_fs(KERNEL_DS);
- show_stacktrace(task, &regs, loglvl);
- set_fs(old_fs);
+ show_stacktrace(task, &regs, loglvl, false);
}

-static void show_code(unsigned int __user *pc)
+static void show_code(unsigned int __user *pc, bool user)
{
long i;
unsigned short __user *pc16 = NULL;
@@ -237,7 +231,8 @@ static void show_code(unsigned int __user *pc)
pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
for(i = -3 ; i < 6 ; i++) {
unsigned int insn;
- if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
+ if (pc16 ? __get_data(insn, pc16 + i, user) :
+ __get_data(insn, pc + i, user)) {
pr_cont(" (Bad address in epc)\n");
break;
}
@@ -356,7 +351,6 @@ void show_regs(struct pt_regs *regs)
void show_registers(struct pt_regs *regs)
{
const int field = 2 * sizeof(unsigned long);
- mm_segment_t old_fs = get_fs();

__show_regs(regs);
print_modules();
@@ -371,13 +365,9 @@ void show_registers(struct pt_regs *regs)
printk("*HwTLS: %0*lx\n", field, tls);
}

- if (!user_mode(regs))
- /* Necessary for getting the correct stack content */
- set_fs(KERNEL_DS);
- show_stacktrace(current, regs, KERN_DEFAULT);
- show_code((unsigned int __user *) regs->cp0_epc);
+ show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
+ show_code((unsigned int __user *) regs->cp0_epc, user_mode(regs));
printk("\n");
- set_fs(old_fs);
}

static DEFINE_RAW_SPINLOCK(die_lock);
@@ -1022,18 +1012,14 @@ asmlinkage void do_bp(struct pt_regs *regs)
unsigned long epc = msk_isa16_mode(exception_epc(regs));
unsigned int opcode, bcode;
enum ctx_state prev_state;
- mm_segment_t seg;
-
- seg = get_fs();
- if (!user_mode(regs))
- set_fs(KERNEL_DS);
+ bool user = user_mode(regs);

prev_state = exception_enter();
current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
if (get_isa16_mode(regs->cp0_epc)) {
u16 instr[2];

- if (__get_user(instr[0], (u16 __user *)epc))
+ if (__get_data(instr[0], (u16 __user *)epc, user))
goto out_sigsegv;

if (!cpu_has_mmips) {
@@ -1044,13 +1030,13 @@ asmlinkage void do_bp(struct pt_regs *regs)
bcode = instr[0] & 0xf;
} else {
/* 32-bit microMIPS BREAK */
- if (__get_user(instr[1], (u16 __user *)(epc + 2)))
+ if (__get_data(instr[1], (u16 __user *)(epc + 2), user))
goto out_sigsegv;
opcode = (instr[0] << 16) | instr[1];
bcode = (opcode >> 6) & ((1 << 20) - 1);
}
} else {
- if (__get_user(opcode, (unsigned int __user *)epc))
+ if (__get_data(opcode, (unsigned int __user *)epc, user))
goto out_sigsegv;
bcode = (opcode >> 6) & ((1 << 20) - 1);
}
@@ -1100,7 +1086,6 @@ asmlinkage void do_bp(struct pt_regs *regs)
do_trap_or_bp(regs, bcode, TRAP_BRKPT, "Break");

out:
- set_fs(seg);
exception_exit(prev_state);
return;

@@ -1114,25 +1099,21 @@ asmlinkage void do_tr(struct pt_regs *regs)
u32 opcode, tcode = 0;
enum ctx_state prev_state;
u16 instr[2];
- mm_segment_t seg;
+ bool user = user_mode(regs);
unsigned long epc = msk_isa16_mode(exception_epc(regs));

- seg = get_fs();
- if (!user_mode(regs))
- set_fs(KERNEL_DS);
-
prev_state = exception_enter();
current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
if (get_isa16_mode(regs->cp0_epc)) {
- if (__get_user(instr[0], (u16 __user *)(epc + 0)) ||
- __get_user(instr[1], (u16 __user *)(epc + 2)))
+ if (__get_data(instr[0], (u16 __user *)(epc + 0), user) ||
+ __get_data(instr[1], (u16 __user *)(epc + 2), user))
goto out_sigsegv;
opcode = (instr[0] << 16) | instr[1];
/* Immediate versions don't provide a code. */
if (!(opcode & OPCODE))
tcode = (opcode >> 12) & ((1 << 4) - 1);
} else {
- if (__get_user(opcode, (u32 __user *)epc))
+ if (__get_data(opcode, (u32 __user *)epc, user))
goto out_sigsegv;
/* Immediate versions don't provide a code. */
if (!(opcode & OPCODE))
@@ -1142,7 +1123,6 @@ asmlinkage void do_tr(struct pt_regs *regs)
do_trap_or_bp(regs, tcode, 0, "Trap");

out:
- set_fs(seg);
exception_exit(prev_state);
return;

@@ -1591,7 +1571,6 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
{
int multi_match = regs->cp0_status & ST0_TS;
enum ctx_state prev_state;
- mm_segment_t old_fs = get_fs();

prev_state = exception_enter();
show_regs(regs);
@@ -1602,12 +1581,7 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
dump_tlb_all();
}

- if (!user_mode(regs))
- set_fs(KERNEL_DS);
-
- show_code((unsigned int __user *) regs->cp0_epc);
-
- set_fs(old_fs);
+ show_code((unsigned int __user *) regs->cp0_epc, user_mode(regs));

/*
* Some chips may have other causes of machine check (e.g. SB1
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 126a5f3f4e4c..fa005cdee0c7 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -112,9 +112,8 @@ static void emulate_load_store_insn(struct pt_regs *regs,
unsigned long origpc, orig31, value;
union mips_instruction insn;
unsigned int res;
-#ifdef CONFIG_EVA
- mm_segment_t seg;
-#endif
+ bool user = user_mode(regs);
+
origpc = (unsigned long)pc;
orig31 = regs->regs[31];

@@ -123,7 +122,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
/*
* This load never faults.
*/
- __get_user(insn.word, pc);
+ __get_data(insn.word, pc, user);

switch (insn.i_format.opcode) {
/*
@@ -163,7 +162,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
if (insn.dsp_format.func == lx_op) {
switch (insn.dsp_format.op) {
case lwx_op:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
@@ -172,7 +171,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
regs->regs[insn.dsp_format.rd] = value;
break;
case lhx_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
@@ -191,93 +190,66 @@ static void emulate_load_store_insn(struct pt_regs *regs,
* memory, so we need to "switch" the address limit to
* user space, so that address check can work properly.
*/
- seg = force_uaccess_begin();
switch (insn.spec3_format.func) {
case lhe_op:
- if (!access_ok(addr, 2)) {
- force_uaccess_end(seg);
+ if (!access_ok(addr, 2))
goto sigbus;
- }
LoadHWE(addr, value, res);
- if (res) {
- force_uaccess_end(seg);
+ if (res)
goto fault;
- }
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lwe_op:
- if (!access_ok(addr, 4)) {
- force_uaccess_end(seg);
+ if (!access_ok(addr, 4))
goto sigbus;
- }
LoadWE(addr, value, res);
- if (res) {
- force_uaccess_end(seg);
+ if (res)
goto fault;
- }
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lhue_op:
- if (!access_ok(addr, 2)) {
- force_uaccess_end(seg);
+ if (!access_ok(addr, 2))
goto sigbus;
- }
LoadHWUE(addr, value, res);
- if (res) {
- force_uaccess_end(seg);
+ if (res)
goto fault;
- }
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case she_op:
- if (!access_ok(addr, 2)) {
- force_uaccess_end(seg);
+ if (!access_ok(addr, 2))
goto sigbus;
- }
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreHWE(addr, value, res);
- if (res) {
- force_uaccess_end(seg);
+ if (res)
goto fault;
- }
break;
case swe_op:
- if (!access_ok(addr, 4)) {
- force_uaccess_end(seg);
+ if (!access_ok(addr, 4))
goto sigbus;
- }
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreWE(addr, value, res);
- if (res) {
- force_uaccess_end(seg);
+ if (res)
goto fault;
- }
break;
default:
- force_uaccess_end(seg);
goto sigill;
}
- force_uaccess_end(seg);
}
#endif
break;
case lh_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

- if (IS_ENABLED(CONFIG_EVA)) {
- if (uaccess_kernel())
- LoadHW(addr, value, res);
- else
- LoadHWE(addr, value, res);
- } else {
+ if (IS_ENABLED(CONFIG_EVA) && user)
+ LoadHWE(addr, value, res);
+ else
LoadHW(addr, value, res);
- }

if (res)
goto fault;
@@ -286,17 +258,13 @@ static void emulate_load_store_insn(struct pt_regs *regs,
break;

case lw_op:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

- if (IS_ENABLED(CONFIG_EVA)) {
- if (uaccess_kernel())
- LoadW(addr, value, res);
- else
- LoadWE(addr, value, res);
- } else {
+ if (IS_ENABLED(CONFIG_EVA) && user)
+ LoadWE(addr, value, res);
+ else
LoadW(addr, value, res);
- }

if (res)
goto fault;
@@ -305,17 +273,13 @@ static void emulate_load_store_insn(struct pt_regs *regs,
break;

case lhu_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

- if (IS_ENABLED(CONFIG_EVA)) {
- if (uaccess_kernel())
- LoadHWU(addr, value, res);
- else
- LoadHWUE(addr, value, res);
- } else {
+ if (IS_ENABLED(CONFIG_EVA) && user)
+ LoadHWUE(addr, value, res);
+ else
LoadHWU(addr, value, res);
- }

if (res)
goto fault;
@@ -332,7 +296,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

LoadWU(addr, value, res);
@@ -355,7 +319,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

LoadDW(addr, value, res);
@@ -370,40 +334,32 @@ static void emulate_load_store_insn(struct pt_regs *regs,
goto sigill;

case sh_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];

- if (IS_ENABLED(CONFIG_EVA)) {
- if (uaccess_kernel())
- StoreHW(addr, value, res);
- else
- StoreHWE(addr, value, res);
- } else {
+ if (IS_ENABLED(CONFIG_EVA) && user)
+ StoreHWE(addr, value, res);
+ else
StoreHW(addr, value, res);
- }

if (res)
goto fault;
break;

case sw_op:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];

- if (IS_ENABLED(CONFIG_EVA)) {
- if (uaccess_kernel())
- StoreW(addr, value, res);
- else
- StoreWE(addr, value, res);
- } else {
+ if (IS_ENABLED(CONFIG_EVA) && user)
+ StoreWE(addr, value, res);
+ else
StoreW(addr, value, res);
- }

if (res)
goto fault;
@@ -418,7 +374,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

compute_return_epc(regs);
@@ -626,6 +582,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
unsigned long origpc, contpc;
union mips_instruction insn;
struct mm_decoded_insn mminsn;
+ bool user = user_mode(regs);

origpc = regs->cp0_epc;
orig31 = regs->regs[31];
@@ -689,7 +646,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if (reg == 31)
goto sigbus;

- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

LoadW(addr, value, res);
@@ -708,7 +665,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if (reg == 31)
goto sigbus;

- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

value = regs->regs[reg];
@@ -728,7 +685,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if (reg == 31)
goto sigbus;

- if (!access_ok(addr, 16))
+ if (user && !access_ok(addr, 16))
goto sigbus;

LoadDW(addr, value, res);
@@ -751,7 +708,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if (reg == 31)
goto sigbus;

- if (!access_ok(addr, 16))
+ if (user && !access_ok(addr, 16))
goto sigbus;

value = regs->regs[reg];
@@ -774,10 +731,10 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
- if (!access_ok(addr, 4 * (rvar + 1)))
+ if (user && !access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
- if (!access_ok(addr, 4 * rvar))
+ if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
@@ -810,10 +767,10 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
- if (!access_ok(addr, 4 * (rvar + 1)))
+ if (user && !access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
- if (!access_ok(addr, 4 * rvar))
+ if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
@@ -847,10 +804,10 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
- if (!access_ok(addr, 8 * (rvar + 1)))
+ if (user && !access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
- if (!access_ok(addr, 8 * rvar))
+ if (user && !access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
@@ -888,10 +845,10 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
- if (!access_ok(addr, 8 * (rvar + 1)))
+ if (user && !access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
- if (!access_ok(addr, 8 * rvar))
+ if (user && !access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
@@ -1010,7 +967,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
case mm_lwm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
- if (!access_ok(addr, 4 * rvar))
+ if (user && !access_ok(addr, 4 * rvar))
goto sigbus;

for (i = 16; rvar; rvar--, i++) {
@@ -1030,7 +987,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
case mm_swm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
- if (!access_ok(addr, 4 * rvar))
+ if (user && !access_ok(addr, 4 * rvar))
goto sigbus;

for (i = 16; rvar; rvar--, i++) {
@@ -1084,7 +1041,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
}

loadHW:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

LoadHW(addr, value, res);
@@ -1094,7 +1051,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
goto success;

loadHWU:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

LoadHWU(addr, value, res);
@@ -1104,7 +1061,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
goto success;

loadW:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

LoadW(addr, value, res);
@@ -1122,7 +1079,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

LoadWU(addr, value, res);
@@ -1144,7 +1101,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

LoadDW(addr, value, res);
@@ -1158,7 +1115,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
goto sigill;

storeHW:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

value = regs->regs[reg];
@@ -1168,7 +1125,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
goto success;

storeW:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

value = regs->regs[reg];
@@ -1186,7 +1143,7 @@ static void emulate_load_store_microMIPS(struct pt_regs *regs,
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

value = regs->regs[reg];
@@ -1243,6 +1200,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
union mips16e_instruction mips16inst, oldinst;
unsigned int opcode;
int extended = 0;
+ bool user = user_mode(regs);

origpc = regs->cp0_epc;
orig31 = regs->regs[31];
@@ -1344,7 +1302,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
goto sigbus;

case MIPS16e_lh_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

LoadHW(addr, value, res);
@@ -1355,7 +1313,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
break;

case MIPS16e_lhu_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

LoadHWU(addr, value, res);
@@ -1368,7 +1326,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
case MIPS16e_lw_op:
case MIPS16e_lwpc_op:
case MIPS16e_lwsp_op:
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

LoadW(addr, value, res);
@@ -1387,7 +1345,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

LoadWU(addr, value, res);
@@ -1411,7 +1369,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

LoadDW(addr, value, res);
@@ -1426,7 +1384,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
goto sigill;

case MIPS16e_sh_op:
- if (!access_ok(addr, 2))
+ if (user && !access_ok(addr, 2))
goto sigbus;

MIPS16e_compute_return_epc(regs, &oldinst);
@@ -1439,7 +1397,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
case MIPS16e_sw_op:
case MIPS16e_swsp_op:
case MIPS16e_i8_op: /* actually - MIPS16e_swrasp_func */
- if (!access_ok(addr, 4))
+ if (user && !access_ok(addr, 4))
goto sigbus;

MIPS16e_compute_return_epc(regs, &oldinst);
@@ -1459,7 +1417,7 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
- if (!access_ok(addr, 8))
+ if (user && !access_ok(addr, 8))
goto sigbus;

MIPS16e_compute_return_epc(regs, &oldinst);
@@ -1516,7 +1474,6 @@ asmlinkage void do_ade(struct pt_regs *regs)
{
enum ctx_state prev_state;
unsigned int __user *pc;
- mm_segment_t seg;

prev_state = exception_enter();
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
@@ -1551,24 +1508,14 @@ asmlinkage void do_ade(struct pt_regs *regs)
show_registers(regs);

if (cpu_has_mmips) {
- seg = get_fs();
- if (!user_mode(regs))
- set_fs(KERNEL_DS);
emulate_load_store_microMIPS(regs,
(void __user *)regs->cp0_badvaddr);
- set_fs(seg);
-
return;
}

if (cpu_has_mips16) {
- seg = get_fs();
- if (!user_mode(regs))
- set_fs(KERNEL_DS);
emulate_load_store_MIPS16e(regs,
(void __user *)regs->cp0_badvaddr);
- set_fs(seg);
-
return;
}

@@ -1579,11 +1526,7 @@ asmlinkage void do_ade(struct pt_regs *regs)
show_registers(regs);
pc = (unsigned int __user *)exception_epc(regs);

- seg = get_fs();
- if (!user_mode(regs))
- set_fs(KERNEL_DS);
emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc);
- set_fs(seg);

return;

--
2.29.2