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amdgcn: Use __builtin_gcn_ in libc/machine/amdgcn/getreent.c 

Call __builtin_gcn_get_stack_limit and __builtin_gcn_first_call_this_thread_p
to reduce dependency on some register/layout assumptions by using the new
GCC mainline (GCC 13) builtins, if they are available. If not, the existing
code is used.
This commit is contained in:
Tobias Burnus 2022-11-22 14:53:48 +01:00 committed by Jeff Johnston
parent b9898fc993
commit b7aca332ce
1 changed files with 29 additions and 9 deletions
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38
newlib/libc/machine/amdgcn/getreent.c
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@ -29,22 +29,42 @@ typedef struct hsa_kernel_dispatch_packet_s {
struct _reent *
__getreent (void)
{
/* Place the reent data at the top of the stack allocation.
s[0:1] contains a 48-bit private segment base address.
/* Place the reent data at the top of the stack allocation. */
struct data {
int marker;
struct _reent reent;
} *data;
#if defined(__has_builtin) \
&& __has_builtin(__builtin_gcn_get_stack_limit) \
&& __has_builtin(__builtin_gcn_first_call_this_thread_p)
unsigned long addr = (((unsigned long) __builtin_gcn_get_stack_limit()
- sizeof(struct data)) & ~7);
data = (struct data *)addr;
register long sp asm("s16");
if (sp >= addr)
goto stackoverflow;
if (__builtin_gcn_first_call_this_thread_p())
{
data->marker = 12345;
__builtin_memset (&data->reent, 0, sizeof(struct _reent));
_REENT_INIT_PTR_ZEROED (&data->reent);
}
else if (data->marker != 12345)
goto stackoverflow;
#else
/* s[0:1] contains a 48-bit private segment base address.
s11 contains the offset to the base of the stack.
s[4:5] contains the dispatch pointer.
WARNING: this code will break if s[0:1] is ever used for anything! */
const register unsigned long buffer_descriptor asm("s0");
unsigned long private_segment = buffer_descriptor & 0x0000ffffffffffff;
const register unsigned int stack_offset asm("s11");
const register hsa_kernel_dispatch_packet_t *dispatch_ptr asm("s4");
struct data {
int marker;
struct _reent reent;
} *data;
unsigned long stack_base = private_segment + stack_offset;
unsigned long stack_end = stack_base + dispatch_ptr->private_segment_size * 64;
unsigned long addr = (stack_end - sizeof(struct data)) & ~7;
@ -69,7 +89,7 @@ __getreent (void)
}
else if (data->marker != 12345)
goto stackoverflow;
#endif
return &data->reent;