search for: __end_rodata_hpage_align

...gt; >Argh, it shouldn't be READONLY for vmlinux either, but apparently that >is working for mysterious reasons. If I'm not mistaken, this works because __bug_table falls outside of the RO range as specified in the vmlinux linker script (using x86_64 as the example, that means _text - __end_rodata_hpage_align). mark_rodata_ro() only sets ro memory protections for pages within this range, so __bug_table remains rw in memory despite its Elf section flags. Interestingly enough, my .rodata section is set 'WA' (rw) in vmlinux on my f25 system, so that leads me to think that Elf section flags in vmlin...

...*/ + if (IS_ENABLED(CONFIG_X86_PIE)) + addr -= 1; return addr; } diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h index 5c019d23d06b..da3d98bb2bcb 100644 --- a/arch/x86/include/asm/sections.h +++ b/arch/x86/include/asm/sections.h @@ -13,4 +13,8 @@ extern char __end_rodata_hpage_align[]; extern char __entry_trampoline_start[], __entry_trampoline_end[]; #endif +#if defined(CONFIG_X86_PIE) +extern char __start_got[], __end_got[]; +#endif + #endif /* _ASM_X86_SECTIONS_H */ diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 01ebcb6f263e..73b3c30cb7a3 100644...

...eturn addr; } diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h index d6baf23782bc..cad292f62eed 100644 --- a/arch/x86/include/asm/sections.h +++ b/arch/x86/include/asm/sections.h @@ -12,4 +12,8 @@ extern struct exception_table_entry __stop___ex_table[]; extern char __end_rodata_hpage_align[]; #endif +#if defined(CONFIG_X86_PIE) +extern char __start_got[], __end_got[]; +#endif + #endif /* _ASM_X86_SECTIONS_H */ diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 01ebcb6f263e..21bde498f1a9 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -1...

On Fri, Jul 14, 2017 at 05:58:18PM +0200, Mike Galbraith wrote: > On Fri, 2017-07-14 at 17:50 +0200, Peter Zijlstra wrote: > > Urgh, is for some mysterious reason the __bug_table section of modules > > ending up in RO memory? > > > > I forever get lost in that link magic :/ > > +1 > > drm.ko >  20

...eturn addr; } diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h index 2f75f30cb2f6..6b2d496cf1aa 100644 --- a/arch/x86/include/asm/sections.h +++ b/arch/x86/include/asm/sections.h @@ -11,4 +11,8 @@ extern struct exception_table_entry __stop___ex_table[]; extern char __end_rodata_hpage_align[]; #endif +#if defined(CONFIG_X86_PIE) +extern char __start_got[], __end_got[]; +#endif + #endif /* _ASM_X86_SECTIONS_H */ diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 9bef1bbeba63..41d8c4c4306d 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -5...

Changes: - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - patch v1: - Simplify ftrace implementation. - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. - rfc v3: - Use --emit-relocs instead of -pie to reduce

Changes: - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - patch v1: - Simplify ftrace implementation. - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. - rfc v3: - Use --emit-relocs instead of -pie to reduce

Changes: - patch v1: - Simplify ftrace implementation. - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. - rfc v3: - Use --emit-relocs instead of -pie to reduce dynamic relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large on modules. Extends

Changes: - patch v1: - Simplify ftrace implementation. - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. - rfc v3: - Use --emit-relocs instead of -pie to reduce dynamic relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large on modules. Extends

These patches make the changes necessary to build the kernel as Position Independent Executable (PIE) on x86_64. A PIE kernel can be relocated below the top 2G of the virtual address space. It allows to optionally extend the KASLR randomization range from 1G to 3G. Thanks a lot to Ard Biesheuvel & Kees Cook on their feedback on compiler changes, PIE support and KASLR in general. Thanks to

These patches make the changes necessary to build the kernel as Position Independent Executable (PIE) on x86_64. A PIE kernel can be relocated below the top 2G of the virtual address space. It allows to optionally extend the KASLR randomization range from 1G to 3G. Thanks a lot to Ard Biesheuvel & Kees Cook on their feedback on compiler changes, PIE support and KASLR in general. Thanks to

Changes: - patch v3: - Update on message to describe longer term PIE goal. - Minor change on ftrace if condition. - Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - patch v1: - Simplify ftrace