On Mon, Mar 13, 2023 at 9:07 PM <crash-utility-request@xxxxxxxxxx> wrote:
Date: Mon, 13 Mar 2023 14:01:11 +0100
From: Juergen Gross <jgross@xxxxxxxx>
To: crash-utility@xxxxxxxxxx
Subject: [Crash-utility] [PATCH 2/3] xen: get stack address via
stack_base array if available
Message-ID: <20230313130112.15353-3-jgross@xxxxxxxx>
Content-Type: text/plain; charset="US-ASCII"; x-default=true
Since many years now the stack address of each percpu stack is
available via the stack_base[] array now. Use that instead of the
indirect method via the percpu variables tss_init or tss_page,
especially as the layout of tss_page has changed in Xen 4.16,
resulting in the stack no longer to be found.
It should be good to add the hypervisor commit(if any) here.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
xen_hyper.c | 50 ++++++++++++++++++++++++++++++--------------------
1 file changed, 30 insertions(+), 20 deletions(-)
diff --git a/xen_hyper.c b/xen_hyper.c
index 1030c0a..72720e2 100644
--- a/xen_hyper.c
+++ b/xen_hyper.c
@@ -324,7 +324,7 @@ void
xen_hyper_x86_pcpu_init(void)
{
ulong cpu_info;
- ulong init_tss_base, init_tss;
+ ulong init_tss_base, init_tss, stack_base;
ulong sp;
struct xen_hyper_pcpu_context *pcc;
char *buf, *bp;
@@ -340,34 +340,44 @@ xen_hyper_x86_pcpu_init(void)
}
/* get physical cpu context */
xen_hyper_alloc_pcpu_context_space(XEN_HYPER_MAX_CPUS());
- if (symbol_exists("per_cpu__init_tss")) {
+ if (symbol_exists("stack_base")) {
+ stack_base = symbol_value("stack_base");
+ flag = 0;
+ } else if (symbol_exists("per_cpu__init_tss")) {
init_tss_base = symbol_value("per_cpu__init_tss");
- flag = TRUE;
+ flag = 1;
} else if (symbol_exists("per_cpu__tss_page")) {
init_tss_base = symbol_value("per_cpu__tss_page");
- flag = TRUE;
+ flag = 1;
} else {
init_tss_base = symbol_value("init_tss");
- flag = FALSE;
+ flag = 2;
}
buf = GETBUF(XEN_HYPER_SIZE(tss));
The buf is not used in the stack_base code path, is it possible to not call the GETBUF() in the stack_base code path?
for_cpu_indexes(i, cpuid)
{
- if (flag)
- init_tss = xen_hyper_per_cpu(init_tss_base, cpuid);
- else
- init_tss = init_tss_base +
- XEN_HYPER_SIZE(tss) * cpuid;
- if (!readmem(init_tss, KVADDR, buf,
- XEN_HYPER_SIZE(tss), "init_tss", RETURN_ON_ERROR)) {
- error(FATAL, "cannot read init_tss.\n");
- }
- if (machine_type("X86")) {
- sp = ULONG(buf + XEN_HYPER_OFFSET(tss_esp0));
- } else if (machine_type("X86_64")) {
- sp = ULONG(buf + XEN_HYPER_OFFSET(tss_rsp0));
- } else
- sp = 0;
+ if (flag) {
+ if (flag == 1)
+ init_tss = xen_hyper_per_cpu(init_tss_base, cpuid);
+ else
+ init_tss = init_tss_base +
+ XEN_HYPER_SIZE(tss) * cpuid;
+ if (!readmem(init_tss, KVADDR, buf,
+ XEN_HYPER_SIZE(tss), "init_tss", RETURN_ON_ERROR)) {
+ error(FATAL, "cannot read init_tss.\n");
+ }
+ if (machine_type("X86")) {
+ sp = ULONG(buf + XEN_HYPER_OFFSET(tss_esp0));
+ } else if (machine_type("X86_64")) {
+ sp = ULONG(buf + XEN_HYPER_OFFSET(tss_rsp0));
+ } else
+ sp = 0;
+ } else {
+ if (!readmem(stack_base + sizeof(ulong) * cpuid, KVADDR, &sp,
+ sizeof(ulong), "stack_base", RETURN_ON_ERROR)) {
+ error(FATAL, "cannot read stack_base.\n");
+ }
The above if(!readmem()) code can be replaced with:
readmem(stack_base + sizeof(ulong) * cpuid, KVADDR, &sp, sizeof(ulong), "stack_base", FAULT_ON_ERROR));
It looks more concise.
Thanks.
Lianbo
+ }
cpu_info = XEN_HYPER_GET_CPU_INFO(sp);
if (CRASHDEBUG(1)) {
fprintf(fp, "sp=%lx, cpu_info=%lx\n", sp, cpu_info);
--
2.35.3
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