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From: Takao Indoh <indou.takao@jp.fujitsu.com>
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To: ats-kumagai@wm.jp.nec.com, d.hatayama@jp.fujitsu.com
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Subject: [makedumpfile PATCH] sadump: Fix a problem of PTI enabled kernel
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Date: Fri, 26 Jan 2018 09:22:26 +0900
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Cc: kexec@lists.infradead.org
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This patch fixes a problme that a dumpfile of sadump cannot be handled by
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makedumpfile when Page Table Isolation(PTI) is enabled.
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When PTI is enabled, bit 12 of CR3 register is used to split user space and
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kernel space. Also bit 11:0 is used for Process Context IDentifiers(PCID).  To
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open a dump file of sadump, a value of CR3 is used to calculate KASLR offset and
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phys_base, therefore this patch fixes to mask CR3 register value collectly for
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PTI enabled kernel.
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Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
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---
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 makedumpfile.c | 2 ++
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 makedumpfile.h | 2 ++
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 sadump_info.c  | 9 ++++++++-
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 3 files changed, 12 insertions(+), 1 deletion(-)
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diff --git a/makedumpfile-1.6.2/makedumpfile.c b/makedumpfile-1.6.2/makedumpfile.c
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index 64b404a..247a056 100644
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--- a/makedumpfile-1.6.2/makedumpfile.c
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+++ b/makedumpfile-1.6.2/makedumpfile.c
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@@ -1557,6 +1557,8 @@ get_symbol_info(void)
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 	SYMBOL_INIT(divide_error, "divide_error");
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 	SYMBOL_INIT(idt_table, "idt_table");
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 	SYMBOL_INIT(saved_command_line, "saved_command_line");
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+	SYMBOL_INIT(pti_init, "pti_init");
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+	SYMBOL_INIT(kaiser_init, "kaiser_init");
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 	return TRUE;
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 }
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diff --git a/makedumpfile-1.6.2/makedumpfile.h b/makedumpfile-1.6.2/makedumpfile.h
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index 57cf4d9..8ee4d29 100644
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--- a/makedumpfile-1.6.2/makedumpfile.h
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+++ b/makedumpfile-1.6.2/makedumpfile.h
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@@ -1608,6 +1608,8 @@ struct symbol_table {
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 	unsigned long long	divide_error;
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 	unsigned long long	idt_table;
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 	unsigned long long	saved_command_line;
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+	unsigned long long	pti_init;
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+	unsigned long long	kaiser_init;
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 	/*
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 	 * symbols on ppc64 arch
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diff --git a/makedumpfile-1.6.2/sadump_info.c b/makedumpfile-1.6.2/sadump_info.c
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index 148d4ba..dd50d48 100644
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--- a/makedumpfile-1.6.2/sadump_info.c
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+++ b/makedumpfile-1.6.2/sadump_info.c
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@@ -1362,6 +1362,9 @@ finish:
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  *    kernel. Retrieve vmcoreinfo from address of "elfcorehdr=" and
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  *    get kaslr_offset and phys_base from vmcoreinfo.
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  */
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+#define PTI_USER_PGTABLE_BIT		(info->page_shift)
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+#define PTI_USER_PGTABLE_MASK		(1 << PTI_USER_PGTABLE_BIT)
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+#define CR3_PCID_MASK			0xFFFull
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 int
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 calc_kaslr_offset(void)
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 {
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@@ -1389,7 +1392,11 @@ calc_kaslr_offset(void)
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 	}
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 	idtr = ((uint64_t)smram.IdtUpper)<<32 | (uint64_t)smram.IdtLower;
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-	cr3 = smram.Cr3;
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+	if ((SYMBOL(pti_init) != NOT_FOUND_SYMBOL) ||
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+	    (SYMBOL(kaiser_init) != NOT_FOUND_SYMBOL))
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+		cr3 = smram.Cr3 & ~(CR3_PCID_MASK|PTI_USER_PGTABLE_MASK);
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+	else
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+		cr3 = smram.Cr3 & ~CR3_PCID_MASK;
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 	/* Convert virtual address of IDT table to physical address */
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 	if ((idtr_paddr = vtop4_x86_64_pagetable(idtr, cr3)) == NOT_PADDR)
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-- 
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1.8.3.1
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