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arch/arm/include/armv7-m/syscall.h: ARM EABI specifies that the stack should be aligned by 8 on function calls, inside the function is not required to be aligned by 8. Since these functions call svc, compiler doesn't know that the svc is a function, therefore it does not do any stack management. This change pushes an even number of args to the stack and maintains an 8 byte alignment. I've checked the assembly and it doesn't cause any more overhead that the hand written assembly.

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This commit is contained in:
Valmantas Palikša
2019-12-16 09:10:03 -06:00
committed by Gregory Nutt
parent 68b0ba88af
commit bc7566a83f
1 changed files with 9 additions and 31 deletions
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arch/arm/include/armv7-m/syscall.h
+9 -31
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@@ -138,23 +138,13 @@ static inline uintptr_t sys_call2(unsigned int nbr, uintptr_t parm1,
/* SVC call with SYS_ call number and three parameters */
static inline uintptr_t sys_call4(unsigned int nbr, uintptr_t parm1,
uintptr_t parm2, uintptr_t parm3,
uintptr_t parm4);
static inline uintptr_t sys_call3(unsigned int nbr, uintptr_t parm1,
uintptr_t parm2, uintptr_t parm3)
{
register long reg0 __asm__("r0") = (long)(nbr);
register long reg3 __asm__("r3") = (long)(parm3);
register long reg2 __asm__("r2") = (long)(parm2);
register long reg1 __asm__("r1") = (long)(parm1);
__asm__ __volatile__
(
"svc %1"
: "=r"(reg0)
: "i"(SYS_syscall), "r"(reg0), "r"(reg1), "r"(reg2), "r"(reg3)
: "memory"
);
return reg0;
return sys_call4(nbr, parm1, parm2, parm3, 0);
}
/* SVC call with SYS_ call number and four parameters.
@@ -189,27 +179,15 @@ static inline uintptr_t sys_call4(unsigned int nbr, uintptr_t parm1,
* NOTE the nonstandard parameter passing: parm4 and parm5 are in R4 and R5
*/
static inline uintptr_t sys_call6(unsigned int nbr, uintptr_t parm1,
uintptr_t parm2, uintptr_t parm3,
uintptr_t parm4, uintptr_t parm5,
uintptr_t parm6);
static inline uintptr_t sys_call5(unsigned int nbr, uintptr_t parm1,
uintptr_t parm2, uintptr_t parm3,
uintptr_t parm4, uintptr_t parm5)
{
register long reg0 __asm__("r0") = (long)(nbr);
register long reg5 __asm__("r5") = (long)(parm5);
register long reg4 __asm__("r4") = (long)(parm4);
register long reg3 __asm__("r3") = (long)(parm3);
register long reg2 __asm__("r2") = (long)(parm2);
register long reg1 __asm__("r1") = (long)(parm1);
__asm__ __volatile__
(
"svc %1"
: "=r"(reg0)
: "i"(SYS_syscall), "r"(reg0), "r"(reg1), "r"(reg2),
"r"(reg3), "r"(reg4), "r"(reg5)
: "memory"
);
return reg0;
return sys_call6(nbr, parm1, parm2, parm3, parm4, parm5, 0);
}
/* SVC call with SYS_ call number and six parameters.