67 lines
2.1 KiB
Diff
67 lines
2.1 KiB
Diff
From 44e5801d9016987b6b4ebd571bfde8ae3e75da7b Mon Sep 17 00:00:00 2001
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From: Philipp Rudo <prudo@redhat.com>
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Date: Thu, 5 Aug 2021 15:19:37 +0200
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Subject: [PATCH 06/27] x86_64: Fix check for __per_cpu_offset initialization
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Since at least kernel v2.6.30 the __per_cpu_offset gets initialized to
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__per_cpu_load. So first check if the __per_cpu_offset was set to a
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proper value before reading any per cpu variable to prevent potential
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bugs.
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[ kh: added check for the existence of __per_cpu_load ]
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Signed-off-by: Philipp Rudo <prudo@redhat.com>
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Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
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---
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x86_64.c | 12 +++++++++++-
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1 file changed, 11 insertions(+), 1 deletion(-)
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diff --git a/x86_64.c b/x86_64.c
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index 6eb7d6708db0..87cbeaeb4f06 100644
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--- a/x86_64.c
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+++ b/x86_64.c
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@@ -1285,6 +1285,7 @@ x86_64_per_cpu_init(void)
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struct machine_specific *ms;
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struct syment *irq_sp, *curr_sp, *cpu_sp, *hardirq_stack_ptr_sp;
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ulong hardirq_stack_ptr;
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+ ulong __per_cpu_load = 0;
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ms = machdep->machspec;
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@@ -1326,7 +1327,12 @@ x86_64_per_cpu_init(void)
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else if (!ms->stkinfo.isize)
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ms->stkinfo.isize = 16384;
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+ if (kernel_symbol_exists("__per_cpu_load"))
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+ __per_cpu_load = symbol_value("__per_cpu_load");
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+
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for (i = cpus = 0; i < NR_CPUS; i++) {
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+ if (__per_cpu_load && kt->__per_cpu_offset[i] == __per_cpu_load)
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+ break;
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if (!readmem(cpu_sp->value + kt->__per_cpu_offset[i],
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KVADDR, &cpunumber, sizeof(int),
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"cpu number (per_cpu)", QUIET|RETURN_ON_ERROR))
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@@ -5595,14 +5601,18 @@ x86_64_get_smp_cpus(void)
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char *cpu_pda_buf;
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ulong level4_pgt, cpu_pda_addr;
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struct syment *sp;
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+ ulong __per_cpu_load = 0;
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if (!VALID_STRUCT(x8664_pda)) {
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if (!(sp = per_cpu_symbol_search("per_cpu__cpu_number")) ||
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!(kt->flags & PER_CPU_OFF))
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return 1;
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+ if (kernel_symbol_exists("__per_cpu_load"))
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+ __per_cpu_load = symbol_value("__per_cpu_load");
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+
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for (i = cpus = 0; i < NR_CPUS; i++) {
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- if (kt->__per_cpu_offset[i] == 0)
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+ if (__per_cpu_load && kt->__per_cpu_offset[i] == __per_cpu_load)
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break;
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if (!readmem(sp->value + kt->__per_cpu_offset[i],
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KVADDR, &cpunumber, sizeof(int),
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--
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2.30.2
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