On Sat, 10 Oct 2020 16:02:10 +0200 Vasily Gorbik <gor@xxxxxxxxxxxxx> wrote: > On Fri, Oct 09, 2020 at 10:49:21PM +0200, Borislav Petkov wrote: > > On Fri, Oct 09, 2020 at 10:38:22PM +0200, Peter Zijlstra wrote: > > > On Wed, Oct 07, 2020 at 04:20:19PM -0000, tip-bot2 for Martin Schwidefsky wrote: > > > > The following commit has been merged into the objtool/core branch of tip: > > > > > > > > Commit-ID: 2a522b53c47051d3bf98748418f4f8e5f20d2c04 > > > > Gitweb: https://git.kernel.org/tip/2a522b53c47051d3bf98748418f4f8e5f20d2c04 > > > > > > > > x86/insn: Support big endian cross-compiles > > > > > > This commit breaks the x86 build with CONFIG_X86_DECODER_SELFTEST=y. > > > > > > I've asked Boris to truncate tip/objtool/core. > > > > Yeah, top 4 are gone until this is resolved. > > > > What I would suggest is to have a look at how tools/ headers are kept > > separate from kernel proper ones, see tools/include/ and how those > > headers there are full of dummy definitions just so it builds. > > > > And then including a global one like linux/kernel.h is just looking for > > trouble: > > > > In file included from ./include/uapi/linux/byteorder/little_endian.h:12, > > from ./include/linux/byteorder/little_endian.h:5, > > from /usr/include/x86_64-linux-gnu/asm/byteorder.h:5, > > from ./arch/x86/include/asm/insn.h:10, > > from arch/x86/tools/insn_sanity.c:21: > > ./tools/include/linux/types.h:30:18: error: conflicting types for ‘u64’ > > 30 | typedef uint64_t u64; > > Sigh... I have not realized there are more usages of insn.c which are > conditionally compiled. It's not like you grep *.c files to find who > includes them regularity. Yes, x86 insn library code is used for the sanity check tool too. > > Looks like there is no way to find common byte swapping helpers for > the kernel and tools then. Even though tools provide quite a bunch of > them in tools/include/. So, completely avoiding mixing "kernel" and > "userspace" headers would look like the following (delta to commit > mentioned above): > --- > > diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h > index 004e27bdf121..68197fe18a11 100644 > --- a/arch/x86/include/asm/insn.h > +++ b/arch/x86/include/asm/insn.h > @@ -7,7 +7,13 @@ > * Copyright (C) IBM Corporation, 2009 > */ > > +#ifdef __KERNEL__ > #include <asm/byteorder.h> > +#define insn_cpu_to_le32 cpu_to_le32 > +#else > +#include <endian.h> > +#define insn_cpu_to_le32 htole32 > +#endif > /* insn_attr_t is defined in inat.h */ > #include <asm/inat.h> > > @@ -47,7 +53,7 @@ static inline void insn_field_set(struct insn_field *p, insn_value_t v, > unsigned char n) > { > p->value = v; > - p->little = __cpu_to_le32(v); > + p->little = insn_cpu_to_le32(v); > p->nbytes = n; > } > > diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c > index 520b31fc1f1a..003f32ff7798 100644 > --- a/arch/x86/lib/insn.c > +++ b/arch/x86/lib/insn.c > @@ -5,7 +5,6 @@ > * Copyright (C) IBM Corporation, 2002, 2004, 2009 > */ > > -#include <linux/kernel.h> > #ifdef __KERNEL__ > #include <linux/string.h> > #else > @@ -16,15 +15,23 @@ > > #include <asm/emulate_prefix.h> > > +#ifdef __KERNEL__ > +#define insn_le32_to_cpu le32_to_cpu > +#define insn_le16_to_cpu le16_to_cpu > +#else > +#define insn_le32_to_cpu le32toh > +#define insn_le16_to_cpu le16toh > +#endif > + > #define leXX_to_cpu(t, r) \ > ({ \ > __typeof__(t) v; \ > switch (sizeof(t)) { \ > - case 4: v = le32_to_cpu(r); break; \ > - case 2: v = le16_to_cpu(r); break; \ > + case 4: v = insn_le32_to_cpu(r); break; \ > + case 2: v = insn_le16_to_cpu(r); break; \ > case 1: v = r; break; \ > - default: \ > - BUILD_BUG(); break; \ > + default: /* relying on -Wuninitialized to report this */ \ > + break; \ > } \ > v; \ > }) > -- > And the same for the tools/* > No linux/kernel.h means no BUILD_BUG(), but -Wuninitialized actually > does a decent job in this case: > arch/x86/../../../arch/x86/lib/insn.c:605:37: error: variable 'v' is > uninitialized when used here [-Werror,-Wuninitialized] > insn_field_set(&insn->immediate2, get_next(long, insn), 1); > ^~~~~~~~~~~~~~~~~~~~ Can you initialize v with 0 ? Anyway it will be optimized out while compiling the code. > > Masami, Josh, > would that be acceptable? Yes. Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
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