12:25 a.m.
Only older kernel (v2.4) used h/w interrupt stack to store frames when
CPU received IPI. Memory used for this in 'struct machine_specific' is
useless for later kernels. For the sake of backward compatibility keep
h/w interrupt stack but dynamically allocate memory for it and save
some bytes from being wasted.
Signed-off-by: Hari Bathini <hbathini(a)linux.ibm.com>
---
Changes in v2:
* Print "(unused)", if hwintrstack is not being used.
defs.h | 2 +-
ppc64.c | 51 +++++++++++++++++++++------------------------------
2 files changed, 22 insertions(+), 31 deletions(-)
diff --git a/defs.h b/defs.h
index 7d3b734..d1d3ea9 100644
--- a/defs.h
+++ b/defs.h
@@ -6303,7 +6303,7 @@ struct ppc64_vmemmap {
* Used to store the HW interrupt stack. It is only for 2.4.
*/
struct machine_specific {
- ulong hwintrstack[NR_CPUS];
+ ulong *hwintrstack;
char *hwstackbuf;
uint hwstacksize;
diff --git a/ppc64.c b/ppc64.c
index 0e1d867..272eb20 100644
--- a/ppc64.c
+++ b/ppc64.c
@@ -256,7 +256,7 @@ static int set_ppc64_max_physmem_bits(void)
}
struct machine_specific ppc64_machine_specific = {
- .hwintrstack = { 0 },
+ .hwintrstack = NULL,
.hwstackbuf = 0,
.hwstacksize = 0,
.pte_rpn_shift = PTE_RPN_SHIFT_DEFAULT,
@@ -275,7 +275,7 @@ struct machine_specific ppc64_machine_specific = {
};
struct machine_specific book3e_machine_specific = {
- .hwintrstack = { 0 },
+ .hwintrstack = NULL,
.hwstackbuf = 0,
.hwstacksize = 0,
.pte_rpn_shift = PTE_RPN_SHIFT_L4_BOOK3E_64K,
@@ -676,6 +676,9 @@ ppc64_init(int when)
*/
offset = MEMBER_OFFSET("paca_struct", "xHrdIntStack");
paca_sym = symbol_value("paca");
+ if (!(machdep->machspec->hwintrstack =
+ (ulong *)calloc(NR_CPUS, sizeof(ulong))))
+ error(FATAL, "cannot malloc hwintrstack space.");
for (cpu = 0; cpu < kt->cpus; cpu++) {
readmem(paca_sym + (paca_size * cpu) + offset,
KVADDR,
@@ -686,14 +689,9 @@ ppc64_init(int when)
machdep->machspec->hwstacksize = 8 * machdep->pagesize;
if ((machdep->machspec->hwstackbuf = (char *)
malloc(machdep->machspec->hwstacksize)) == NULL)
- error(FATAL, "cannot malloc hwirqstack space.");
- } else
- /*
- * 'xHrdIntStack' member in "paca_struct" is not
- * available for 2.6 kernel.
- */
- BZERO(&machdep->machspec->hwintrstack,
- NR_CPUS*sizeof(ulong));
+ error(FATAL, "cannot malloc hwirqstack buffer space.");
+ }
+
if (!machdep->hz) {
machdep->hz = HZ;
if (THIS_KERNEL_VERSION >= LINUX(2,6,0))
@@ -846,23 +844,15 @@ ppc64_dump_machdep_table(ulong arg)
fprintf(fp, " is_vmaddr: %s\n",
machdep->machspec->is_vmaddr == book3e_is_vmaddr ?
"book3e_is_vmaddr()" : "ppc64_is_vmaddr()");
- fprintf(fp, " hwintrstack[%d]: ", NR_CPUS);
- for (c = 0; c < NR_CPUS; c++) {
- for (others = 0, i = c; i < NR_CPUS; i++) {
- if (machdep->machspec->hwintrstack[i])
- others++;
+ if (machdep->machspec->hwintrstack) {
+ fprintf(fp, " hwintrstack[%d]: ", NR_CPUS);
+ for (c = 0; c < NR_CPUS; c++) {
+ fprintf(fp, "%s%016lx ",
+ ((c % 4) == 0) ? "\n " : "",
+ machdep->machspec->hwintrstack[c]);
}
- if (!others) {
- fprintf(fp, "%s%s",
- c && ((c % 4) == 0) ? "\n " : "",
- c ? "(remainder unused)" : "(unused)");
- break;
- }
-
- fprintf(fp, "%s%016lx ",
- ((c % 4) == 0) ? "\n " : "",
- machdep->machspec->hwintrstack[c]);
- }
+ } else
+ fprintf(fp, " hwintrstack: (unused)");
fprintf(fp, "\n");
fprintf(fp, " hwstackbuf: %lx\n",
(ulong)machdep->machspec->hwstackbuf);
fprintf(fp, " hwstacksize: %d\n",
machdep->machspec->hwstacksize);
@@ -1683,9 +1673,10 @@ ppc64_check_sp_in_HWintrstack(ulong sp, struct bt_info *bt)
*
* Note: HW Interrupt stack is used only in 2.4 kernel.
*/
- if (is_task_active(bt->task) && (tt->panic_task != bt->task)
&&
- machdep->machspec->hwintrstack[bt->tc->processor]) {
+ if (machdep->machspec->hwintrstack && is_task_active(bt->task)
&&
+ (bt->task != tt->panic_task)) {
ulong newsp;
+
readmem(machdep->machspec->hwintrstack[bt->tc->processor],
KVADDR, &newsp, sizeof(ulong),
"stack pointer", FAULT_ON_ERROR);
@@ -1958,7 +1949,7 @@ ppc64_back_trace(struct gnu_request *req, struct bt_info *bt)
bt->stackbase = irqstack;
bt->stacktop = bt->stackbase + STACKSIZE();
alter_stackbuf(bt);
- } else if (ms->hwintrstack[bt->tc->processor]) {
+ } else if (ms->hwintrstack) {
bt->stacktop = ms->hwintrstack[bt->tc->processor] +
sizeof(ulong);
bt->stackbase = ms->hwintrstack[bt->tc->processor] -
@@ -2555,7 +2546,7 @@ retry:
goto retry;
}
- if (check_intrstack && ms->hwintrstack[bt->tc->processor]) {
+ if (check_intrstack && ms->hwintrstack) {
bt->stacktop = ms->hwintrstack[bt->tc->processor] +
sizeof(ulong);
bt->stackbase = ms->hwintrstack[bt->tc->processor] -
--
2.35.3