On 15.03.23 06:36, lijiang wrote:
On Mon, Mar 13, 2023 at 9:07 PM <crash-utility-request@xxxxxxxxxx
<mailto:crash-utility-request@xxxxxxxxxx>> wrote:
Date: Mon, 13 Mar 2023 14:01:11 +0100
From: Juergen Gross <jgross@xxxxxxxx <mailto:jgross@xxxxxxxx>>
To: crash-utility@xxxxxxxxxx <mailto: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
<mailto: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 <mailto: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?
Yes, of course.
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.
Okay. Juergen
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