Messages in this thread | | | Date | Fri, 27 Mar 2020 12:02:32 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH 05/70] x86/insn: Make inat-tables.c suitable for pre-decompression code |
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Hi,
On Wed, 25 Mar 2020 16:39:45 +0100 Borislav Petkov <bp@alien8.de> wrote:
> + Masami. > > On Thu, Mar 19, 2020 at 10:13:02AM +0100, Joerg Roedel wrote: > > From: Joerg Roedel <jroedel@suse.de> > > > > 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.
> > Signed-off-by: Joerg Roedel <jroedel@suse.de> > > --- > > 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?
> > + > > + 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.
> > + 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 <mhiramat@kernel.org>
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