Artifact e98ef79662b3a8becb3950ba82f139ac612b729926aedc741351b53608065256:
- File mod/kmem/heapao.fn.c — part of check-in [e50a476efe] at 2019-08-22 02:52:20 on branch trunk — removed sneaky segfault in x86-64 syscall fn where %r8 (the register that contains the pointer to the syscall arguments from the C syscall wrapper, which need to be copied into the correct registers before the kernel is invoked) gets overwritten if the syscall valency > 5, because of overlapping ccall and syscall ABI argument registers - r8 is clobbered by argument 5 and any further attempts to use it as a ptr segfault at best. also modified the report function so that it immediate cancels compilation if a sub-process reports failure. changed allocator function signatures so they can return a condition code if the kernel reports an error; updated example code so it compiles and runs without fault. (user: lexi, size: 500) [annotate] [blame] [check-ins using]
#include <k/core.h>
#include <k/mem.h>
/* heapao.fn.c - kmheapao() "allocate heap object"
* ~ lexi hale <lexi@hale.su>
* kmheapao() allocates a region in heap memory
* and returns a kmptr struct referencing that
* newly allocated region.
*/
kmcond kmheapao(kmptr* where, sz size) {
void* ptr;
kmcond e = kmheapa(&ptr, size);
if (e != kmcond_ok) return e;
kmptr p = {
.kind = (ptr != null ? kmkind_heap : kmkind_fail),
.ref = ptr,
.shred = false,
};
*where = p;
return kmcond_ok;
}