minix/kernel/arch/i386/breakpoints.c

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2010-04-02 00:22:33 +02:00
#include "kernel/kernel.h"
#include "arch_proto.h"
#include "debugreg.h"
PRIVATE int breakpoint_set(phys_bytes linaddr, int bp, const int flags)
{
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unsigned long dr7, dr7flags;
if (bp >= BREAKPOINT_COUNT)
return EINVAL;
/* convert flags */
dr7flags = 0;
switch (flags & BREAKPOINT_FLAG_RW_MASK) {
case BREAKPOINT_FLAG_RW_EXEC: dr7flags |= DR7_RW_EXEC(bp); break;
case BREAKPOINT_FLAG_RW_WRITE: dr7flags |= DR7_RW_WRITE(bp); break;
case BREAKPOINT_FLAG_RW_RW: dr7flags |= DR7_RW_RW(bp); break;
default: return EINVAL;
}
switch (flags & BREAKPOINT_FLAG_LEN_MASK) {
case BREAKPOINT_FLAG_LEN_1: dr7flags |= DR7_LN_1(bp); break;
case BREAKPOINT_FLAG_LEN_2: dr7flags |= DR7_LN_2(bp); break;
case BREAKPOINT_FLAG_LEN_4: dr7flags |= DR7_LN_4(bp); break;
default: return EINVAL;
}
switch (flags & BREAKPOINT_FLAG_MODE_MASK) {
case BREAKPOINT_FLAG_MODE_OFF: break;
case BREAKPOINT_FLAG_MODE_LOCAL: dr7flags |= DR7_L(bp); break;
case BREAKPOINT_FLAG_MODE_GLOBAL: dr7flags |= DR7_G(bp); break;
default: return EINVAL;
}
/* disable breakpoint before setting address */
dr7 = st_dr7();
dr7 &= ~(DR7_L(bp) | DR7_G(bp) | DR7_RW_MASK(bp) | DR7_LN_MASK(bp));
ld_dr7(dr7);
/* need to set new breakpoint? */
if ((flags & BREAKPOINT_FLAG_MODE_MASK) == BREAKPOINT_FLAG_MODE_OFF)
return 0;
/* set breakpoint address */
switch (bp) {
case 0: ld_dr0(linaddr); break;
case 1: ld_dr1(linaddr); break;
case 2: ld_dr2(linaddr); break;
case 3: ld_dr3(linaddr); break;
default: panic("%s:%d: invalid breakpoint index", __FILE__, __LINE__);
}
/* set new flags */
dr7 |= dr7flags;
ld_dr7(dr7);
return 0;
}