BMC/Intel-BMC/linux.git/arch/powerpc/kernel/entry_32.S, branch dev-4.10

powerpc: Revert the initial stack protector support

2017-01-24T10:37:43+00:00

Unfortunately the stack protector support we merged recently only works on some toolchains. If the toolchain is built without glibc support everything works fine, but if glibc is built then it leads to a panic at boot. The solution is not rc5 material, so revert the support for now. This reverts commits: 6533b7c16ee5 ("powerpc: Initial stack protector (-fstack-protector) support") 902e06eb86cd ("powerpc/32: Change the stack protector canary value per task") Fixes: 6533b7c16ee5 ("powerpc: Initial stack protector (-fstack-protector) support") Signed-off-by: Michael Ellerman

powerpc/32: Change the stack protector canary value per task

2016-11-23T11:57:20+00:00

Partially copied from commit df0698be14c66 ("ARM: stack protector: change the canary value per task") A new random value for the canary is stored in the task struct whenever a new task is forked. This is meant to allow for different canary values per task. On powerpc, GCC expects the canary value to be found in a global variable called __stack_chk_guard. So this variable has to be updated with the value stored in the task struct whenever a task switch occurs. Because the variable GCC expects is global, this cannot work on SMP unfortunately. So, on SMP, the same initial canary value is kept throughout, making this feature a bit less effective although it is still useful. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2016-10-14T21:26:58+00:00

Pull kbuild updates from Michal Marek: - EXPORT_SYMBOL for asm source by Al Viro. This does bring a regression, because genksyms no longer generates checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is working on a patch to fix this. Plus, we are talking about functions like strcpy(), which rarely change prototypes. - Fixes for PPC fallout of the above by Stephen Rothwell and Nick Piggin - fixdep speedup by Alexey Dobriyan. - preparatory work by Nick Piggin to allow architectures to build with -ffunction-sections, -fdata-sections and --gc-sections - CONFIG_THIN_ARCHIVES support by Stephen Rothwell - fix for filenames with colons in the initramfs source by me. * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits) initramfs: Escape colons in depfile ppc: there is no clear_pages to export powerpc/64: whitelist unresolved modversions CRCs kbuild: -ffunction-sections fix for archs with conflicting sections kbuild: add arch specific post-link Makefile kbuild: allow archs to select link dead code/data elimination kbuild: allow architectures to use thin archives instead of ld -r kbuild: Regenerate genksyms lexer kbuild: genksyms fix for typeof handling fixdep: faster CONFIG_ search ia64: move exports to definitions sparc32: debride memcpy.S a bit [sparc] unify 32bit and 64bit string.h sparc: move exports to definitions ppc: move exports to definitions arm: move exports to definitions s390: move exports to definitions m68k: move exports to definitions alpha: move exports to actual definitions x86: move exports to actual definitions ...

powerpc/32: Remove CLR_TOP32

2016-09-22T21:54:22+00:00

CLR_TOP32() is defined as blank. Last useful instance of CLR_TOP32() was removed by commit 40ef8cbc6d360 ("powerpc: Get 64-bit configs to compile with ARCH=powerpc") in 2005. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

ppc: move exports to definitions

2016-08-08T03:50:09+00:00

Signed-off-by: Al Viro

powerpc32: provide VIRT_CPU_ACCOUNTING

2016-07-09T06:43:50+00:00

This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. PPC32 doesn't have the PACA structure, so we use the task_info structure to store the accounting data. In order to reuse on PPC32 the PPC64 functions, all u64 data has been replaced by 'unsigned long' so that it is u32 on PPC32 and u64 on PPC64 Signed-off-by: Christophe Leroy Signed-off-by: Scott Wood

powerpc/kernel: Change the do_syscall_trace_enter() API

2015-07-29T01:56:11+00:00

The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman Reviewed-by: Kees Cook

powerpc/kernel: Switch to using MAX_ERRNO

2015-07-29T01:56:11+00:00

Currently on powerpc we have our own #define for the highest (negative) errno value, called _LAST_ERRNO. This is defined to be 516, for reasons which are not clear. The generic code, and x86, use MAX_ERRNO, which is defined to be 4095. In particular seccomp uses MAX_ERRNO to restrict the value that a seccomp filter can return. Currently with the mismatch between _LAST_ERRNO and MAX_ERRNO, a seccomp tracer wanting to return 600, expecting it to be seen as an error, would instead find on powerpc that userspace sees a successful syscall with a return value of 600. To avoid this inconsistency, switch powerpc to use MAX_ERRNO. We are somewhat confident that generic syscalls that can return a non-error value above negative MAX_ERRNO have already been updated to use force_successful_syscall_return(). I have also checked all the powerpc specific syscalls, and believe that none of them expect to return a non-error value between -MAX_ERRNO and -516. So this change should be safe ... Acked-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman Reviewed-by: Kees Cook

powerpc: Remove old compile time disabled syscall tracing code

2015-02-02T03:51:32+00:00

We have code to do syscall tracing which is disabled at compile time by default. It's not been touched since the dawn of time (ie. v2.6.12). There are now better ways to do syscall tracing, ie. using the raw_syscall, or syscall tracepoints. For the specific case of tracing syscalls at boot on a system that doesn't get to userspace, you can boot with: trace_event=syscalls tp_printk=on Which will trace syscalls from boot, and echo all output to the console. Signed-off-by: Michael Ellerman

powerpc: Rename _TIF_SYSCALL_T_OR_A to _TIF_SYSCALL_DOTRACE

2015-01-23T03:02:51+00:00

Once upon a time, at least 9 years ago (< 2.6.12), _TIF_SYSCALL_T_OR_A meant "TRACE or AUDIT". But these days it means TRACE or AUDIT or SECCOMP or TRACEPOINT or NOHZ. All of those are implemented via syscall_dotrace() so rename the flag to that to try and clarify things. Signed-off-by: Michael Ellerman