Hi,

On Wed, 25 Mar 2020 16:39:45 +0100
Borislav Petkov [off-list ref] wrote:

+ Masami.

On Thu, Mar 19, 2020 at 10:13:02AM +0100, Joerg Roedel wrote:

quoted

From: Joerg Roedel <redacted>

The inat-tables.c file has some arrays in it that contain pointers to
other arrays. These pointers need to be relocated when the kernel
image is moved to a different location.

The pre-decompression boot-code has no support for applying ELF
relocations, so initialize these arrays at runtime in the
pre-decompression code to make sure all pointers are correctly
initialized.

I need to check the whole series, but as far as I can understand from
this patch, this seems not allowing to store the address value in
static pointers. It may break more things, for example _kprobe_blacklist
records the NOKPROBE_SYMBOL() symbol addresses at the build time.

I have some comments here.
 

quoted

Signed-off-by: Joerg Roedel <redacted>
---
 arch/x86/tools/gen-insn-attr-x86.awk       | 50 +++++++++++++++++++++-
 tools/arch/x86/tools/gen-insn-attr-x86.awk | 50 +++++++++++++++++++++-
 2 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/arch/x86/tools/gen-insn-attr-x86.awk b/arch/x86/tools/gen-insn-attr-x86.awk
index a42015b305f4..af38469afd14 100644
--- a/arch/x86/tools/gen-insn-attr-x86.awk
+++ b/arch/x86/tools/gen-insn-attr-x86.awk

@@ -362,6 +362,9 @@ function convert_operands(count,opnd,       i,j,imm,mod)
 END {
 	if (awkchecked != "")
 		exit 1
+
+	print "#ifndef __BOOT_COMPRESSED\n"
+
 	# print escape opcode map's array
 	print "/* Escape opcode map array */"
 	print "const insn_attr_t * const inat_escape_tables[INAT_ESC_MAX + 1]" \

@@ -388,6 +391,51 @@ END {
 		for (j = 0; j < max_lprefix; j++)
 			if (atable[i,j])
 				print "	["i"]["j"] = "atable[i,j]","
-	print "};"
+	print "};\n"
+
+	print "#else /* !__BOOT_COMPRESSED */\n"

I think the definitions of inat_*_tables can be shared in both case.
If __BOOT_COMPRESSED is set, we can define inat_init_tables() as a
initialize function, and if not, it will be just a dummy "do {} while (0)".

BTW, where is the __BOOT_COMPRESSED defined?

quoted

+
+	print "/* Escape opcode map array */"
+	print "static const insn_attr_t *inat_escape_tables[INAT_ESC_MAX + 1]" \
+	      "[INAT_LSTPFX_MAX + 1];"
+	print ""
+
+	print "/* Group opcode map array */"
+	print "static const insn_attr_t *inat_group_tables[INAT_GRP_MAX + 1]"\
+	      "[INAT_LSTPFX_MAX + 1];"
+	print ""
+
+	print "/* AVX opcode map array */"
+	print "static const insn_attr_t *inat_avx_tables[X86_VEX_M_MAX + 1]"\
+	      "[INAT_LSTPFX_MAX + 1];"
+	print ""
+
+	print "static void inat_init_tables(void)"

This functions should be "inline".
And I can not see the call-site of inat_init_tables() in this patch.

If possible, please include call-site with definition (especially
new init function) so that I can check the init call timing too.

quoted

+	print "{"
+
+	# print escape opcode map's array
+	print "\t/* Print Escape opcode map array */"
+	for (i = 0; i < geid; i++)
+		for (j = 0; j < max_lprefix; j++)
+			if (etable[i,j])
+				print "\tinat_escape_tables["i"]["j"] = "etable[i,j]";"
+	print ""
+
+	# print group opcode map's array
+	print "\t/* Print Group opcode map array */"
+	for (i = 0; i < ggid; i++)
+		for (j = 0; j < max_lprefix; j++)
+			if (gtable[i,j])
+				print "\tinat_group_tables["i"]["j"] = "gtable[i,j]";"
+	print ""
+	# print AVX opcode map's array
+	print "\t/* Print AVX opcode map array */"
+	for (i = 0; i < gaid; i++)
+		for (j = 0; j < max_lprefix; j++)
+			if (atable[i,j])
+				print "\tinat_avx_tables["i"]["j"] = "atable[i,j]";"
+
+	print "}"
+	print "#endif"
 }

The code itself looks good to me.

Thank you,

-- 
Masami Hiramatsu [off-list ref]