Fixes for the umip test
PATCH v3 1/1 Fixes for the umip test
When compiling umip.c with -O2 instead of -O1, there are currently two problems. First, the compiler complains:
x86/umip.c: In function ‘do_ring3’:
x86/umip.c:162:37: error: array subscript 4096 is above array bounds of
‘unsigned char[4096]’ [-Werror=array-bounds]
[user_stack_top]"m"(user_stack[sizeof user_stack]),
~~~~~~~~~~^~~~~~~~~~~~~~~~~~~This can be fixed by initializing the stack to point to one of the last bytes of the array instead.
The second problem is that some tests are failing - and this is due to the fact that the GP_ASM macro uses inline asm without the "volatile" keyword - so that the compiler reorders this code in certain cases where it should not. Fix it by adding "volatile" here.
---
v3: Use "sizeof(long)" instead of "2"
x86/umip.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
x86/umip.c +4 -2
@@ -22,7 +22,8 @@ static void gp_handler(struct ex_regs *regs)#define GP_ASM (stmt, in, clobber) \ - asm ("mov" W " $1f, %[expected_rip]\n\t" \ + asm volatile ( \ + "mov" W " $1f, %[expected_rip]\n\t" \ "movl $2f-1f, %[skip_count]\n\t" \ "1: " stmt "\n\t" \ "2: " \
@@ -159,7 +160,8 @@ static int do_ring3(void (*fn)(const char *), const char *arg) : [ret] "=&a" (ret) : [user_ds] "i" (USER_DS), [user_cs] "i" (USER_CS), - [user_stack_top]"m"(user_stack[sizeof user_stack]), + [user_stack_top]"m"(user_stack[sizeof(user_stack) - + sizeof(long)]), [fn]"r"(fn), [arg]"D"(arg), [kernel_ds]"i"(KERNEL_DS),
Signature · 1 line
2.18.1
Paolo Bonzini
maintainerQuoted 41 lines · Thomas Huth
When compiling
umip.cwith -O2 instead of -O1, there are currently two problems. First, the compiler complains:
x86/umip.c: In function ‘do_ring3’:
x86/umip.c:162:37: error: array subscript 4096 is above array bounds of‘unsigned char[4096]’ [-Werror=array-bounds] [user_stack_top]"m"(user_stack[sizeof user_stack]), ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~This can be fixed by initializing the stack to point to one of the last bytes of the array instead.
The second problem is that some tests are failing - and this is due to the fact that the
GP_ASMmacro uses inline asm without the "volatile" keyword - so that the compiler reorders this code in certain cases where it should not. Fix it by adding "volatile" here.Reviewed-by Vitaly Kuznetsov <[email protected]>Signed-off-by Thomas Huth <[email protected]>---
v3: Use "sizeof(long)" instead of "2"x86/umip.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)x86/umip.c +2
-1@@ -22,7 +22,8 @@ static void gp_handler(struct ex_regs *regs)#define GP_ASM (stmt, in, clobber) \ - asm ("mov" W " $1f, %[expected_rip]\n\t" \ + asm volatile ( \ + "mov" W " $1f, %[expected_rip]\n\t" \ "movl $2f-1f, %[skip_count]\n\t" \ "1: " stmt "\n\t" \ "2: " \
x86/umip.c static int do_ring3(void (*fn)(const char *), const char *arg) · line 167
Quoted 9 lines
x86/umip.c +2
-1@@ -159,7 +160,8 @@ static int do_ring3(void (*fn)(const char *), const char *arg) : [ret] "=&a" (ret) : [user_ds] "i" (USER_DS), [user_cs] "i" (USER_CS), - [user_stack_top]"m"(user_stack[sizeof user_stack]), + [user_stack_top]"m"(user_stack[sizeof(user_stack) - + sizeof(long)]), [fn]"r"(fn), [arg]"D"(arg), [kernel_ds]"i"(KERNEL_DS),
Pushed, thanks.
Paolo