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Where is the set_c0_status() function defined?

The code at:

https://github.com/intel/linux-intel-4.9/blob/master/arch/mips/cavium-octeon/octeon-irq.c

Uses the function or macro set_c0_status()

Where is that defined?
If this is built into the GCC MIPS compiler, then where is it documented ?

2 Answers
2

I found this in arch/mips/kvm/kvm_mips.c

static
void kvm_mips_set_c0_status (void)
{
uint32_t status = read_c0_status();

if (cpu_has_fpu)
status |= (ST0_CU1);

if (cpu_has_dsp)
status |= (ST0_MX);

write_c0_status(status);
__asm volatile ("ehb");
}


and the write_c0_status is defined in mipsregs.h ( https://elixir.bootlin.com/linux/latest/source/arch/mips/include/asm/mipsregs.h#L1639 ), So I guess you should look there for the answer.

The set_c0_status function is defined in mipsregs.h and expanded by the following macro hierarchy:

set_c0_status

mipsregs.h

https://github.com/torvalds/linux/blob/master/arch/mips/include/asm/mipsregs.h

/*
* Manipulate bits in a register.
*/
#define __BUILD_SET_COMMON(name)
static inline unsigned int

set_##name(unsigned int set)
{
unsigned int res, new;

res = read_##name();
new = res | set;
write_##name(new);

return res;
}

...

/*
* Manipulate bits in a c0 register.
*/
#define __BUILD_SET_C0(name) __BUILD_SET_COMMON(c0_##name)

__BUILD_SET_C0(status)


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