* [PATCHv4 2/3] powerpc, cpu: handling the special case when boot_cpuid greater than nr_cpus
From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: kexec, mahesh, cascardo, gpiccoli, paulus, benh, mpe
In-Reply-To: <1520829790-14029-1-git-send-email-kernelfans@gmail.com>
For kexec -p, after boot_cpuid is mapping into the range of [0,
threads_per_core), then if nr_cpus is small, we will have the bitmap
[0,..., nr_cpus, ..., boot_cpuid, ...). This patch chooses cpus inside
the range of [boot_cpuid - nr_cpus +1, ..., boot_cpuid] to be online.
With this patch and the next, on a P9 machine with thread_per_core=4,
and set nr_cpus=2 for the crash kernel.
After
taskset -c 11 sh -c "echo c > /proc/sysrq-trigger"
Then
kdump:/sys/devices/system/cpu# cat possible
2-3
kdump:/sys/devices/system/cpu# cat present
2-3
kdump:/sys/devices/system/cpu# cat online
2-3
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
---
arch/powerpc/kernel/setup-common.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 1a67344..6920b5e 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -462,6 +462,8 @@ void __init smp_setup_cpu_maps(void)
struct device_node *dn;
struct device_node *boot_dn = NULL;
bool handling_bootdn = true;
+ int head_thread = 0;
+ int online_cnt = 0;
int cpu = 0;
int nthreads = 1;
@@ -499,13 +501,19 @@ void __init smp_setup_cpu_maps(void)
if (boot_cpuid < nthreads &&
be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) {
boot_dn = dn;
+ /* choose a bunch of continous threads */
+ if (boot_cpuid > nr_cpu_ids - 1) {
+ head_thread = boot_cpuid - nr_cpu_ids + 1;
+ /* keep the mapping of logical and thread */
+ cpu = head_thread;
+ }
}
if (boot_dn == NULL)
continue;
} else if (dn == boot_dn)
continue;
- for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
+ for (j = head_thread; j < nthreads && online_cnt < nr_cpu_ids; j++) {
bool avail;
DBG(" thread %d -> cpu %d (hard id %d)\n",
@@ -520,13 +528,15 @@ void __init smp_setup_cpu_maps(void)
set_hard_smp_processor_id(cpu, be32_to_cpu(intserv[j]));
set_cpu_possible(cpu, true);
cpu++;
+ online_cnt++;
}
- if (cpu >= nr_cpu_ids) {
+ if (online_cnt >= nr_cpu_ids) {
of_node_put(dn);
break;
}
if (handling_bootdn) {
+ head_thread = 0;
handling_bootdn = false;
goto again;
}
--
2.7.4
^ permalink raw reply related
* [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt
From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: kexec, mahesh, cascardo, gpiccoli, paulus, benh, mpe
In-Reply-To: <1520829790-14029-1-git-send-email-kernelfans@gmail.com>
For kexec -p, the boot cpu can be not the cpu0, this causes the problem
to alloc paca[]. In theory, there is no requirement to assign cpu's logical
id as its present seq by device tree. But we have something like
cpu_first_thread_sibling(), which makes assumption on the mapping inside
a core. Hence partially changing the mapping, i.e. unbind the mapping of
core while keep the mapping inside a core. After this patch, boot-cpu
will always be mapped into the range [0,threads_per_core).
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
---
arch/powerpc/include/asm/smp.h | 1 +
arch/powerpc/kernel/prom.c | 25 ++++++++++++++-----------
arch/powerpc/kernel/setup-common.c | 21 +++++++++++++++++++++
3 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index fac963e..1299100 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -30,6 +30,7 @@
#include <asm/percpu.h>
extern int boot_cpuid;
+extern int boot_cpuhwid;
extern int spinning_secondaries;
extern void cpu_die(void);
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index da67606..d0ebb25 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -315,8 +315,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
const __be32 *intserv;
int i, nthreads;
int len;
- int found = -1;
- int found_thread = 0;
+ bool found = false;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
@@ -341,8 +340,11 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
if (fdt_version(initial_boot_params) >= 2) {
if (be32_to_cpu(intserv[i]) ==
fdt_boot_cpuid_phys(initial_boot_params)) {
- found = boot_cpu_count;
- found_thread = i;
+ /* always map the boot-cpu logical id into the
+ * the range of [0, thread_per_core)
+ */
+ boot_cpuid = i;
+ found = true;
}
} else {
/*
@@ -351,8 +353,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
* off secondary threads.
*/
if (of_get_flat_dt_prop(node,
- "linux,boot-cpu", NULL) != NULL)
- found = boot_cpu_count;
+ "linux,boot-cpu", NULL) != NULL) {
+ boot_cpuid = i;
+ found = true;
+ }
}
#ifdef CONFIG_SMP
/* logical cpu id is always 0 on UP kernels */
@@ -361,13 +365,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
}
/* Not the boot CPU */
- if (found < 0)
+ if (!found)
return 0;
- DBG("boot cpu: logical %d physical %d\n", found,
- be32_to_cpu(intserv[found_thread]));
- boot_cpuid = found;
- set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread]));
+ boot_cpuhwid = be32_to_cpu(intserv[boot_cpuid]);
+ DBG("boot cpu: logical %d physical %d\n", boot_cpuid, boot_cpuhwid);
+ set_hard_smp_processor_id(boot_cpuid, boot_cpuhwid);
/*
* PAPR defines "logical" PVR values for cpus that
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 66f7cc6..1a67344 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -86,6 +86,7 @@ struct machdep_calls *machine_id;
EXPORT_SYMBOL(machine_id);
int boot_cpuid = -1;
+int boot_cpuhwid = -1;
EXPORT_SYMBOL_GPL(boot_cpuid);
/*
@@ -459,11 +460,17 @@ static void __init cpu_init_thread_core_maps(int tpc)
void __init smp_setup_cpu_maps(void)
{
struct device_node *dn;
+ struct device_node *boot_dn = NULL;
+ bool handling_bootdn = true;
int cpu = 0;
int nthreads = 1;
DBG("smp_setup_cpu_maps()\n");
+again:
+ /* E.g. kexec will not boot from the 1st core. So firstly loop to find out
+ * the dn of boot-cpu, and map them onto [0, nthreads)
+ */
for_each_node_by_type(dn, "cpu") {
const __be32 *intserv;
__be32 cpu_be;
@@ -488,6 +495,16 @@ void __init smp_setup_cpu_maps(void)
nthreads = len / sizeof(int);
+ if (handling_bootdn) {
+ if (boot_cpuid < nthreads &&
+ be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) {
+ boot_dn = dn;
+ }
+ if (boot_dn == NULL)
+ continue;
+ } else if (dn == boot_dn)
+ continue;
+
for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
bool avail;
@@ -509,6 +526,10 @@ void __init smp_setup_cpu_maps(void)
of_node_put(dn);
break;
}
+ if (handling_bootdn) {
+ handling_bootdn = false;
+ goto again;
+ }
}
/* If no SMT supported, nthreads is forced to 1 */
--
2.7.4
^ permalink raw reply related
* [PATCHv4 0/3] enable nr_cpus for powerpc
From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: kexec, mahesh, cascardo, gpiccoli, paulus, benh, mpe
This topic has a very long history. It comes from Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
For v3: https://patchwork.ozlabs.org/patch/834860/
In this series, I separate and change the mapping between cpu logical id and hwid.
I hope we can acquire it for "kexec -p"
Mahesh Salgaonkar (1):
ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to
hit.
Pingfan Liu (2):
powerpc, cpu: partially unbind the mapping between cpu logical id and
its seq in dt
powerpc, cpu: handling the special case when boot_cpuid greater than
nr_cpus
arch/powerpc/include/asm/paca.h | 3 +++
arch/powerpc/include/asm/smp.h | 1 +
arch/powerpc/kernel/paca.c | 19 ++++++++++++++-----
arch/powerpc/kernel/prom.c | 25 ++++++++++++++-----------
arch/powerpc/kernel/setup-common.c | 35 +++++++++++++++++++++++++++++++++--
5 files changed, 65 insertions(+), 18 deletions(-)
--
2.7.4
^ permalink raw reply
* Re: [PATCH v8 2/6] module: allow symbol exports to be disabled
From: Nicolas Pitre @ 2018-03-11 21:31 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-arm-kernel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Josh Poimboeuf,
Steven Rostedt, Sergey Senozhatsky, Linus Torvalds, Jessica Yu,
linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-3-ard.biesheuvel@linaro.org>
On Sun, 11 Mar 2018, Ard Biesheuvel wrote:
> To allow existing C code to be incorporated into the decompressor or
> the UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx
> declarations into nops, and #define it in places where such exports
> are undesirable. Note that this gets rid of a rather dodgy redefine
> of linux/export.h's header guard.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
> ---
> arch/x86/boot/compressed/kaslr.c | 5 +----
> drivers/firmware/efi/libstub/Makefile | 3 ++-
> include/linux/export.h | 11 ++++++++++-
> 3 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index 8199a6187251..3a2a6d7049e4 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -23,11 +23,8 @@
> * _ctype[] in lib/ctype.c is needed by isspace() of linux/ctype.h.
> * While both lib/ctype.c and lib/cmdline.c will bring EXPORT_SYMBOL
> * which is meaningless and will cause compiling error in some cases.
> - * So do not include linux/export.h and define EXPORT_SYMBOL(sym)
> - * as empty.
> */
> -#define _LINUX_EXPORT_H
> -#define EXPORT_SYMBOL(sym)
> +#define __DISABLE_EXPORTS
>
> #include "misc.h"
> #include "error.h"
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index 7b3ba40f0745..896a882c89f4 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -20,7 +20,8 @@ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
> KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
> -D__NO_FORTIFY \
> $(call cc-option,-ffreestanding) \
> - $(call cc-option,-fno-stack-protector)
> + $(call cc-option,-fno-stack-protector) \
> + -D__DISABLE_EXPORTS
>
> GCOV_PROFILE := n
> KASAN_SANITIZE := n
> diff --git a/include/linux/export.h b/include/linux/export.h
> index 1a1dfdb2a5c6..25005b55b079 100644
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -72,7 +72,16 @@ extern struct module __this_module;
> __attribute__((section("___ksymtab" sec "+" #sym), used)) \
> = { (unsigned long)&sym, __kstrtab_##sym }
>
> -#if defined(__KSYM_DEPS__)
> +#if defined(__DISABLE_EXPORTS)
> +
> +/*
> + * Allow symbol exports to be disabled completely so that C code may
> + * be reused in other execution contexts such as the UEFI stub or the
> + * decompressor.
> + */
> +#define __EXPORT_SYMBOL(sym, sec)
> +
> +#elif defined(__KSYM_DEPS__)
>
> /*
> * For fine grained build dependencies, we want to tell the build system
> --
> 2.15.1
>
>
^ permalink raw reply
* Re: [PATCH v8 1/6] arch: enable relative relocations for arm64, power and x86
From: Linus Torvalds @ 2018-03-11 21:23 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-arm-kernel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky, Jessica Yu,
Linux Kernel Mailing List, ppc-dev, the arch/x86 maintainers
In-Reply-To: <CAKv+Gu_E8mVqaR9OmzP2whc7WHGaFX5ypCh7F0UHEyY1DY_t3Q@mail.gmail.com>
On Sun, Mar 11, 2018 at 1:35 PM, Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
>
> I'm sure all of these architectures define some kind of 32-bit place
> relative relocation in their ELF psABI, and I see how it would be
> cleaner to change everything at once, but I anticipate a long tail of
> issues with toolchains for niche architectures that I have no way to
> test.
Ok, fair enough.
Linus
^ permalink raw reply
* Re: [PATCH v8 1/6] arch: enable relative relocations for arm64, power and x86
From: Ard Biesheuvel @ 2018-03-11 20:35 UTC (permalink / raw)
To: Linus Torvalds
Cc: linux-arm-kernel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky, Jessica Yu,
Linux Kernel Mailing List, ppc-dev, the arch/x86 maintainers
In-Reply-To: <CA+55aFxcB+5oB_hL83EASOJQrVRCrzT9iS+2+XtEUToG6VHiqA@mail.gmail.com>
On 11 March 2018 at 20:20, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sun, Mar 11, 2018 at 5:38 AM, Ard Biesheuvel
> <ard.biesheuvel@linaro.org> wrote:
>> Before updating certain subsystems to use place relative 32-bit
>> relocations in special sections, to save space and reduce the
>> number of absolute relocations that need to be processed at runtime
>> by relocatable kernels, introduce the Kconfig symbol and define it
>> for some architectures that should be able to support and benefit
>> from it.
>
> Are there actually architectures hat _don't_ support those relative
> 32-bit relocations? That really feels pretty fundamental.
>
I started out doing all of them, and I don't remember the exact list,
but there are quite a few architectures that don't support these
relocations in their module loaders, and in fact, not even ARM does
(as one of the 'big' architectures).
This is not really surprising, given that the C compiler never emits
such relative references.
> I would have expected all of them to do it - is your selection of
> arm64/powerpc/x86 perhaps more about "I have tested these" than about
> anything else?
>
> Because I'd almost prefer to just do the switch-over unconditionally
> if that is at all possible?
>
arm64, powerpc and x86 implement CONFIG_RELOCATABLE, and so they
benefit more than other architectures, because of the fact that the
relocation metadata for these data structures can be dropped entirely.
Other 64-bit architectures only have the 50% size reduction benefit,
and 32-bit architectures have no benefit at all.
I'm sure all of these architectures define some kind of 32-bit place
relative relocation in their ELF psABI, and I see how it would be
cleaner to change everything at once, but I anticipate a long tail of
issues with toolchains for niche architectures that I have no way to
test.
^ permalink raw reply
* Re: [PATCH v8 1/6] arch: enable relative relocations for arm64, power and x86
From: Linus Torvalds @ 2018-03-11 20:20 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-arm-kernel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky, Jessica Yu,
Linux Kernel Mailing List, ppc-dev, the arch/x86 maintainers
In-Reply-To: <20180311123815.17916-2-ard.biesheuvel@linaro.org>
On Sun, Mar 11, 2018 at 5:38 AM, Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
> Before updating certain subsystems to use place relative 32-bit
> relocations in special sections, to save space and reduce the
> number of absolute relocations that need to be processed at runtime
> by relocatable kernels, introduce the Kconfig symbol and define it
> for some architectures that should be able to support and benefit
> from it.
Are there actually architectures hat _don't_ support those relative
32-bit relocations? That really feels pretty fundamental.
I would have expected all of them to do it - is your selection of
arm64/powerpc/x86 perhaps more about "I have tested these" than about
anything else?
Because I'd almost prefer to just do the switch-over unconditionally
if that is at all possible?
Linus
^ permalink raw reply
* Re: [PATCH v8 0/6] add support for relative references in special sections
From: Kees Cook @ 2018-03-11 19:08 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-arm-kernel, Arnd Bergmann, Will Deacon, Michael Ellerman,
Thomas Garnier, Thomas Gleixner, Serge E. Hallyn, Bjorn Helgaas,
Benjamin Herrenschmidt, Russell King, Paul Mackerras,
Catalin Marinas, Petr Mladek, Ingo Molnar, Andrew Morton,
Nicolas Pitre, Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, Linux Kernel Mailing List,
linuxppc-dev, the arch/x86 maintainers, James Morris
In-Reply-To: <CAKv+Gu9X7THvdZtoshSQbYGmAHvi+TdaqiM9ienASG-3-Zv88w@mail.gmail.com>
On Sun, Mar 11, 2018 at 5:44 AM, Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
> On 11 March 2018 at 12:38, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> Cc: James Morris <james.l.morris@oracle.com>
>
> Note when replying: this ^^^ email address no longer works.
James updated MAINTAINERS to: James Morris <jmorris@namei.org>
--
Kees Cook
Pixel Security
^ permalink raw reply
* Re: [PATCH v8 3/6] module: use relative references for __ksymtab entries
From: Ard Biesheuvel @ 2018-03-11 14:12 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, Andrew Morton, Nicolas Pitre, Josh Poimboeuf,
Steven Rostedt, Sergey Senozhatsky, Linus Torvalds, Jessica Yu,
Linux Kernel Mailing List, linuxppc-dev, the arch/x86 maintainers,
Ingo Molnar
In-Reply-To: <20180311123815.17916-4-ard.biesheuvel@linaro.org>
On 11 March 2018 at 12:38, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab
> entries, each consisting of two 64-bit fields containing absolute
> references, to the symbol itself and to a char array containing
> its name, respectively.
>
> When we build the same configuration with KASLR enabled, we end
> up with an additional ~192 KB of relocations in the .init section,
> i.e., one 24 byte entry for each absolute reference, which all need
> to be processed at boot time.
>
> Given how the struct kernel_symbol that describes each entry is
> completely local to module.c (except for the references emitted
> by EXPORT_SYMBOL() itself), we can easily modify it to contain
> two 32-bit relative references instead. This reduces the size of
> the __ksymtab section by 50% for all 64-bit architectures, and
> gets rid of the runtime relocations entirely for architectures
> implementing KASLR, either via standard PIE linking (arm64) or
> using custom host tools (x86).
>
> Note that the binary search involving __ksymtab contents relies
> on each section being sorted by symbol name. This is implemented
> based on the input section names, not the names in the ksymtab
> entries, so this patch does not interfere with that.
>
> Given that the use of place-relative relocations requires support
> both in the toolchain and in the module loader, we cannot enable
> this feature for all architectures. So make it dependent on whether
> CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.
>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Thomas Garnier <thgarnie@google.com>
> Cc: Nicolas Pitre <nico@linaro.org>
> Acked-by: Jessica Yu <jeyu@kernel.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/x86/include/asm/Kbuild | 1 +
> arch/x86/include/asm/export.h | 5 ---
> include/asm-generic/export.h | 12 ++++-
> include/linux/compiler.h | 19 ++++++++
> include/linux/export.h | 46 +++++++++++++++-----
> kernel/module.c | 32 +++++++++++---
> 6 files changed, 91 insertions(+), 24 deletions(-)
>
...
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index ab4711c63601..0a9328ea9dbd 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -280,6 +280,25 @@ unsigned long read_word_at_a_time(const void *addr)
>
> #endif /* __KERNEL__ */
>
> +/*
> + * Force the compiler to emit 'sym' as a symbol, so that we can reference
> + * it from inline assembler. Necessary in case 'sym' could be inlined
> + * otherwise, or eliminated entirely due to lack of references that are
> + * visible to the compiler.
> + */
> +#define __ADDRESSABLE(sym) \
> + static void * const __attribute__((section(".discard"), used)) \
> + __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
> +
kernelci.org tells me that I need to drop the 'const' here, or we may
end up with .discard sections with conflicting attributes (r/o vs r/w)
in some cases (CONFIG_DEBUG_FORCE_WEAK_PER_CPU=y)
^ permalink raw reply
* Re: [PATCH v8 0/6] add support for relative references in special sections
From: Ard Biesheuvel @ 2018-03-11 12:44 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, Linux Kernel Mailing List,
linuxppc-dev, the arch/x86 maintainers
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
On 11 March 2018 at 12:38, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
...
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Thomas Garnier <thgarnie@google.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: "Serge E. Hallyn" <serge@hallyn.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Morris <james.l.morris@oracle.com>
Note when replying: this ^^^ email address no longer works.
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Nicolas Pitre <nico@linaro.org>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Jessica Yu <jeyu@kernel.org>
>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: x86@kernel.org
>
...
^ permalink raw reply
* [PATCH v8 6/6] kernel: tracepoints: add support for relative references
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
To avoid the need for relocating absolute references to tracepoint
structures at boot time when running relocatable kernels (which may
take a disproportionate amount of space), add the option to emit
these tables as relative references instead.
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
include/linux/tracepoint.h | 19 ++++++--
kernel/tracepoint.c | 49 +++++++++++---------
2 files changed, 41 insertions(+), 27 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c94f466d57ef..cdb0a9461d71 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -225,6 +225,19 @@ extern void syscall_unregfunc(void);
return static_key_false(&__tracepoint_##name.key); \
}
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define __TRACEPOINT_ENTRY(name) \
+ asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \
+ " .balign 4 \n" \
+ " .long " VMLINUX_SYMBOL_STR(__tracepoint_##name) " - .\n" \
+ " .previous \n")
+#else
+#define __TRACEPOINT_ENTRY(name) \
+ static struct tracepoint * const __tracepoint_ptr_##name __used \
+ __attribute__((section("__tracepoints_ptrs"))) = \
+ &__tracepoint_##name
+#endif
+
/*
* We have no guarantee that gcc and the linker won't up-align the tracepoint
* structures, so we create an array of pointers that will be used for iteration
@@ -234,11 +247,9 @@ extern void syscall_unregfunc(void);
static const char __tpstrtab_##name[] \
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
- __attribute__((section("__tracepoints"))) = \
+ __attribute__((section("__tracepoints"), used)) = \
{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
- static struct tracepoint * const __tracepoint_ptr_##name __used \
- __attribute__((section("__tracepoints_ptrs"))) = \
- &__tracepoint_##name;
+ __TRACEPOINT_ENTRY(name);
#define DEFINE_TRACE(name) \
DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 671b13457387..4ce8cc4bf2c3 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -326,6 +326,27 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
}
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
+static void for_each_tracepoint_range(struct tracepoint * const *begin,
+ struct tracepoint * const *end,
+ void (*fct)(struct tracepoint *tp, void *priv),
+ void *priv)
+{
+ if (!begin)
+ return;
+
+ if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) {
+ const int *iter;
+
+ for (iter = (const int *)begin; iter < (const int *)end; iter++)
+ fct(offset_to_ptr(iter), priv);
+ } else {
+ struct tracepoint * const *iter;
+
+ for (iter = begin; iter < end; iter++)
+ fct(*iter, priv);
+ }
+}
+
#ifdef CONFIG_MODULES
bool trace_module_has_bad_taint(struct module *mod)
{
@@ -390,15 +411,9 @@ EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
* Ensure the tracer unregistered the module's probes before the module
* teardown is performed. Prevents leaks of probe and data pointers.
*/
-static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
- struct tracepoint * const *end)
+static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
{
- struct tracepoint * const *iter;
-
- if (!begin)
- return;
- for (iter = begin; iter < end; iter++)
- WARN_ON_ONCE((*iter)->funcs);
+ WARN_ON_ONCE(tp->funcs);
}
static int tracepoint_module_coming(struct module *mod)
@@ -449,8 +464,9 @@ static void tracepoint_module_going(struct module *mod)
* Called the going notifier before checking for
* quiescence.
*/
- tp_module_going_check_quiescent(mod->tracepoints_ptrs,
- mod->tracepoints_ptrs + mod->num_tracepoints);
+ for_each_tracepoint_range(mod->tracepoints_ptrs,
+ mod->tracepoints_ptrs + mod->num_tracepoints,
+ tp_module_going_check_quiescent, NULL);
break;
}
}
@@ -502,19 +518,6 @@ static __init int init_tracepoints(void)
__initcall(init_tracepoints);
#endif /* CONFIG_MODULES */
-static void for_each_tracepoint_range(struct tracepoint * const *begin,
- struct tracepoint * const *end,
- void (*fct)(struct tracepoint *tp, void *priv),
- void *priv)
-{
- struct tracepoint * const *iter;
-
- if (!begin)
- return;
- for (iter = begin; iter < end; iter++)
- fct(*iter, priv);
-}
-
/**
* for_each_kernel_tracepoint - iteration on all kernel tracepoints
* @fct: callback
--
2.15.1
^ permalink raw reply related
* [PATCH v8 5/6] PCI: Add support for relative addressing in quirk tables
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
Allow the PCI quirk tables to be emitted in a way that avoids absolute
references to the hook functions. This reduces the size of the entries,
and, more importantly, makes them invariant under runtime relocation
(e.g., for KASLR)
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
drivers/pci/quirks.c | 12 +++++++++---
include/linux/pci.h | 20 ++++++++++++++++++++
2 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8b14bd326d4a..24abfaccd2a0 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3563,9 +3563,15 @@ static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
f->vendor == (u16) PCI_ANY_ID) &&
(f->device == dev->device ||
f->device == (u16) PCI_ANY_ID)) {
- calltime = fixup_debug_start(dev, f->hook);
- f->hook(dev);
- fixup_debug_report(dev, calltime, f->hook);
+ void (*hook)(struct pci_dev *dev);
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ hook = offset_to_ptr(&f->hook_offset);
+#else
+ hook = f->hook;
+#endif
+ calltime = fixup_debug_start(dev, hook);
+ hook(dev);
+ fixup_debug_report(dev, calltime, hook);
}
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 024a1beda008..765044bb9e8e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1790,7 +1790,11 @@ struct pci_fixup {
u16 device; /* Or PCI_ANY_ID */
u32 class; /* Or PCI_ANY_ID */
unsigned int class_shift; /* should be 0, 8, 16 */
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ int hook_offset;
+#else
void (*hook)(struct pci_dev *dev);
+#endif
};
enum pci_fixup_pass {
@@ -1804,12 +1808,28 @@ enum pci_fixup_pass {
pci_fixup_suspend_late, /* pci_device_suspend_late() */
};
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \
+ class_shift, hook) \
+ __ADDRESSABLE(hook) \
+ asm(".section " #sec ", \"a\" \n" \
+ ".balign 16 \n" \
+ ".short " #vendor ", " #device " \n" \
+ ".long " #class ", " #class_shift " \n" \
+ ".long " VMLINUX_SYMBOL_STR(hook) " - . \n" \
+ ".previous \n");
+#define DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \
+ class_shift, hook) \
+ __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \
+ class_shift, hook)
+#else
/* Anonymous variables would be nice... */
#define DECLARE_PCI_FIXUP_SECTION(section, name, vendor, device, class, \
class_shift, hook) \
static const struct pci_fixup __PASTE(__pci_fixup_##name,__LINE__) __used \
__attribute__((__section__(#section), aligned((sizeof(void *))))) \
= { vendor, device, class, class_shift, hook };
+#endif
#define DECLARE_PCI_FIXUP_CLASS_EARLY(vendor, device, class, \
class_shift, hook) \
--
2.15.1
^ permalink raw reply related
* [PATCH v8 4/6] init: allow initcall tables to be emitted using relative references
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
include/linux/init.h | 44 +++++++++++++++-----
init/main.c | 32 +++++++-------
kernel/printk/printk.c | 4 +-
security/security.c | 4 +-
4 files changed, 53 insertions(+), 31 deletions(-)
diff --git a/include/linux/init.h b/include/linux/init.h
index 506a98151131..cca0f76bf4a6 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -116,8 +116,24 @@
typedef int (*initcall_t)(void);
typedef void (*exitcall_t)(void);
-extern initcall_t __con_initcall_start[], __con_initcall_end[];
-extern initcall_t __security_initcall_start[], __security_initcall_end[];
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+typedef int initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+ return offset_to_ptr(entry);
+}
+#else
+typedef initcall_t initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+ return *entry;
+}
+#endif
+
+extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
+extern initcall_entry_t __security_initcall_start[], __security_initcall_end[];
/* Used for contructor calls. */
typedef void (*ctor_fn_t)(void);
@@ -167,9 +183,20 @@ extern bool initcall_debug;
* as KEEP() in the linker script.
*/
-#define __define_initcall(fn, id) \
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define ___define_initcall(fn, id, __sec) \
+ __ADDRESSABLE(fn) \
+ asm(".section \"" #__sec ".init\", \"a\" \n" \
+ "__initcall_" #fn #id ": \n" \
+ ".long " VMLINUX_SYMBOL_STR(fn) " - . \n" \
+ ".previous \n");
+#else
+#define ___define_initcall(fn, id, __sec) \
static initcall_t __initcall_##fn##id __used \
- __attribute__((__section__(".initcall" #id ".init"))) = fn;
+ __attribute__((__section__(#__sec ".init"))) = fn;
+#endif
+
+#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
/*
* Early initcalls run before initializing SMP.
@@ -208,13 +235,8 @@ extern bool initcall_debug;
#define __exitcall(fn) \
static exitcall_t __exitcall_##fn __exit_call = fn
-#define console_initcall(fn) \
- static initcall_t __initcall_##fn \
- __used __section(.con_initcall.init) = fn
-
-#define security_initcall(fn) \
- static initcall_t __initcall_##fn \
- __used __section(.security_initcall.init) = fn
+#define console_initcall(fn) ___define_initcall(fn,, .con_initcall)
+#define security_initcall(fn) ___define_initcall(fn,, .security_initcall)
struct obs_kernel_param {
const char *str;
diff --git a/init/main.c b/init/main.c
index a8100b954839..d81487cc126d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -848,18 +848,18 @@ int __init_or_module do_one_initcall(initcall_t fn)
}
-extern initcall_t __initcall_start[];
-extern initcall_t __initcall0_start[];
-extern initcall_t __initcall1_start[];
-extern initcall_t __initcall2_start[];
-extern initcall_t __initcall3_start[];
-extern initcall_t __initcall4_start[];
-extern initcall_t __initcall5_start[];
-extern initcall_t __initcall6_start[];
-extern initcall_t __initcall7_start[];
-extern initcall_t __initcall_end[];
-
-static initcall_t *initcall_levels[] __initdata = {
+extern initcall_entry_t __initcall_start[];
+extern initcall_entry_t __initcall0_start[];
+extern initcall_entry_t __initcall1_start[];
+extern initcall_entry_t __initcall2_start[];
+extern initcall_entry_t __initcall3_start[];
+extern initcall_entry_t __initcall4_start[];
+extern initcall_entry_t __initcall5_start[];
+extern initcall_entry_t __initcall6_start[];
+extern initcall_entry_t __initcall7_start[];
+extern initcall_entry_t __initcall_end[];
+
+static initcall_entry_t *initcall_levels[] __initdata = {
__initcall0_start,
__initcall1_start,
__initcall2_start,
@@ -885,7 +885,7 @@ static char *initcall_level_names[] __initdata = {
static void __init do_initcall_level(int level)
{
- initcall_t *fn;
+ initcall_entry_t *fn;
strcpy(initcall_command_line, saved_command_line);
parse_args(initcall_level_names[level],
@@ -895,7 +895,7 @@ static void __init do_initcall_level(int level)
NULL, &repair_env_string);
for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
- do_one_initcall(*fn);
+ do_one_initcall(initcall_from_entry(fn));
}
static void __init do_initcalls(void)
@@ -926,10 +926,10 @@ static void __init do_basic_setup(void)
static void __init do_pre_smp_initcalls(void)
{
- initcall_t *fn;
+ initcall_entry_t *fn;
for (fn = __initcall_start; fn < __initcall0_start; fn++)
- do_one_initcall(*fn);
+ do_one_initcall(initcall_from_entry(fn));
}
/*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fc1123583fa6..0be1e8524873 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2780,7 +2780,7 @@ EXPORT_SYMBOL(unregister_console);
*/
void __init console_init(void)
{
- initcall_t *call;
+ initcall_entry_t *call;
/* Setup the default TTY line discipline. */
n_tty_init();
@@ -2791,7 +2791,7 @@ void __init console_init(void)
*/
call = __con_initcall_start;
while (call < __con_initcall_end) {
- (*call)();
+ initcall_from_entry(call)();
call++;
}
}
diff --git a/security/security.c b/security/security.c
index 1cd8526cb0b7..f648eeff06de 100644
--- a/security/security.c
+++ b/security/security.c
@@ -45,10 +45,10 @@ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
static void __init do_security_initcalls(void)
{
- initcall_t *call;
+ initcall_entry_t *call;
call = __security_initcall_start;
while (call < __security_initcall_end) {
- (*call) ();
+ initcall_from_entry(call)();
call++;
}
}
--
2.15.1
^ permalink raw reply related
* [PATCH v8 3/6] module: use relative references for __ksymtab entries
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86,
Ingo Molnar
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab
entries, each consisting of two 64-bit fields containing absolute
references, to the symbol itself and to a char array containing
its name, respectively.
When we build the same configuration with KASLR enabled, we end
up with an additional ~192 KB of relocations in the .init section,
i.e., one 24 byte entry for each absolute reference, which all need
to be processed at boot time.
Given how the struct kernel_symbol that describes each entry is
completely local to module.c (except for the references emitted
by EXPORT_SYMBOL() itself), we can easily modify it to contain
two 32-bit relative references instead. This reduces the size of
the __ksymtab section by 50% for all 64-bit architectures, and
gets rid of the runtime relocations entirely for architectures
implementing KASLR, either via standard PIE linking (arm64) or
using custom host tools (x86).
Note that the binary search involving __ksymtab contents relies
on each section being sorted by symbol name. This is implemented
based on the input section names, not the names in the ksymtab
entries, so this patch does not interfere with that.
Given that the use of place-relative relocations requires support
both in the toolchain and in the module loader, we cannot enable
this feature for all architectures. So make it dependent on whether
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Nicolas Pitre <nico@linaro.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/x86/include/asm/Kbuild | 1 +
arch/x86/include/asm/export.h | 5 ---
include/asm-generic/export.h | 12 ++++-
include/linux/compiler.h | 19 ++++++++
include/linux/export.h | 46 +++++++++++++++-----
kernel/module.c | 32 +++++++++++---
6 files changed, 91 insertions(+), 24 deletions(-)
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index de690c2d2e33..a0ab9ab61c75 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -8,5 +8,6 @@ generated-y += xen-hypercalls.h
generic-y += dma-contiguous.h
generic-y += early_ioremap.h
+generic-y += export.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
diff --git a/arch/x86/include/asm/export.h b/arch/x86/include/asm/export.h
deleted file mode 100644
index 2a51d66689c5..000000000000
--- a/arch/x86/include/asm/export.h
+++ /dev/null
@@ -1,5 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifdef CONFIG_64BIT
-#define KSYM_ALIGN 16
-#endif
-#include <asm-generic/export.h>
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 719db1968d81..97ce606459ae 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -5,12 +5,10 @@
#define KSYM_FUNC(x) x
#endif
#ifdef CONFIG_64BIT
-#define __put .quad
#ifndef KSYM_ALIGN
#define KSYM_ALIGN 8
#endif
#else
-#define __put .long
#ifndef KSYM_ALIGN
#define KSYM_ALIGN 4
#endif
@@ -25,6 +23,16 @@
#define KSYM(name) name
#endif
+.macro __put, val, name
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ .long \val - ., \name - .
+#elif defined(CONFIG_64BIT)
+ .quad \val, \name
+#else
+ .long \val, \name
+#endif
+.endm
+
/*
* note on .section use: @progbits vs %progbits nastiness doesn't matter,
* since we immediately emit into those sections anyway.
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index ab4711c63601..0a9328ea9dbd 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -280,6 +280,25 @@ unsigned long read_word_at_a_time(const void *addr)
#endif /* __KERNEL__ */
+/*
+ * Force the compiler to emit 'sym' as a symbol, so that we can reference
+ * it from inline assembler. Necessary in case 'sym' could be inlined
+ * otherwise, or eliminated entirely due to lack of references that are
+ * visible to the compiler.
+ */
+#define __ADDRESSABLE(sym) \
+ static void * const __attribute__((section(".discard"), used)) \
+ __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
+
+/**
+ * offset_to_ptr - convert a relative memory offset to an absolute pointer
+ * @off: the address of the 32-bit offset value
+ */
+static inline void *offset_to_ptr(const int *off)
+{
+ return (void *)((unsigned long)off + *off);
+}
+
#endif /* __ASSEMBLY__ */
#ifndef __optimize
diff --git a/include/linux/export.h b/include/linux/export.h
index 25005b55b079..04c78e6bfec9 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -24,12 +24,6 @@
#define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)
#ifndef __ASSEMBLY__
-struct kernel_symbol
-{
- unsigned long value;
- const char *name;
-};
-
#ifdef MODULE
extern struct module __this_module;
#define THIS_MODULE (&__this_module)
@@ -60,17 +54,47 @@ extern struct module __this_module;
#define __CRC_SYMBOL(sym, sec)
#endif
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#include <linux/compiler.h>
+/*
+ * Emit the ksymtab entry as a pair of relative references: this reduces
+ * the size by half on 64-bit architectures, and eliminates the need for
+ * absolute relocations that require runtime processing on relocatable
+ * kernels.
+ */
+#define __KSYMTAB_ENTRY(sym, sec) \
+ __ADDRESSABLE(sym) \
+ asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
+ " .balign 8 \n" \
+ VMLINUX_SYMBOL_STR(__ksymtab_##sym) ": \n" \
+ " .long " VMLINUX_SYMBOL_STR(sym) "- . \n" \
+ " .long " VMLINUX_SYMBOL_STR(__kstrtab_##sym) "- .\n" \
+ " .previous \n")
+
+struct kernel_symbol {
+ int value_offset;
+ int name_offset;
+};
+#else
+#define __KSYMTAB_ENTRY(sym, sec) \
+ static const struct kernel_symbol __ksymtab_##sym \
+ __attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ = { (unsigned long)&sym, __kstrtab_##sym }
+
+struct kernel_symbol {
+ unsigned long value;
+ const char *name;
+};
+#endif
+
/* For every exported symbol, place a struct in the __ksymtab section */
#define ___EXPORT_SYMBOL(sym, sec) \
extern typeof(sym) sym; \
__CRC_SYMBOL(sym, sec) \
static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"), aligned(1))) \
+ __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
= VMLINUX_SYMBOL_STR(sym); \
- static const struct kernel_symbol __ksymtab_##sym \
- __used \
- __attribute__((section("___ksymtab" sec "+" #sym), used)) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+ __KSYMTAB_ENTRY(sym, sec)
#if defined(__DISABLE_EXPORTS)
diff --git a/kernel/module.c b/kernel/module.c
index ad2d420024f6..b4782cfbb79b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -549,12 +549,30 @@ static bool check_symbol(const struct symsearch *syms,
return true;
}
+static unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ return (unsigned long)offset_to_ptr(&sym->value_offset);
+#else
+ return sym->value;
+#endif
+}
+
+static const char *kernel_symbol_name(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ return offset_to_ptr(&sym->name_offset);
+#else
+ return sym->name;
+#endif
+}
+
static int cmp_name(const void *va, const void *vb)
{
const char *a;
const struct kernel_symbol *b;
a = va; b = vb;
- return strcmp(a, b->name);
+ return strcmp(a, kernel_symbol_name(b));
}
static bool find_symbol_in_section(const struct symsearch *syms,
@@ -2198,7 +2216,7 @@ void *__symbol_get(const char *symbol)
sym = NULL;
preempt_enable();
- return sym ? (void *)sym->value : NULL;
+ return sym ? (void *)kernel_symbol_value(sym) : NULL;
}
EXPORT_SYMBOL_GPL(__symbol_get);
@@ -2228,10 +2246,12 @@ static int verify_export_symbols(struct module *mod)
for (i = 0; i < ARRAY_SIZE(arr); i++) {
for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
- if (find_symbol(s->name, &owner, NULL, true, false)) {
+ if (find_symbol(kernel_symbol_name(s), &owner, NULL,
+ true, false)) {
pr_err("%s: exports duplicate symbol %s"
" (owned by %s)\n",
- mod->name, s->name, module_name(owner));
+ mod->name, kernel_symbol_name(s),
+ module_name(owner));
return -ENOEXEC;
}
}
@@ -2280,7 +2300,7 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
ksym = resolve_symbol_wait(mod, info, name);
/* Ok if resolved. */
if (ksym && !IS_ERR(ksym)) {
- sym[i].st_value = ksym->value;
+ sym[i].st_value = kernel_symbol_value(ksym);
break;
}
@@ -2540,7 +2560,7 @@ static int is_exported(const char *name, unsigned long value,
ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
else
ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
- return ks != NULL && ks->value == value;
+ return ks != NULL && kernel_symbol_value(ks) == value;
}
/* As per nm */
--
2.15.1
^ permalink raw reply related
* [PATCH v8 2/6] module: allow symbol exports to be disabled
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
To allow existing C code to be incorporated into the decompressor or
the UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx
declarations into nops, and #define it in places where such exports
are undesirable. Note that this gets rid of a rather dodgy redefine
of linux/export.h's header guard.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/x86/boot/compressed/kaslr.c | 5 +----
drivers/firmware/efi/libstub/Makefile | 3 ++-
include/linux/export.h | 11 ++++++++++-
3 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 8199a6187251..3a2a6d7049e4 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -23,11 +23,8 @@
* _ctype[] in lib/ctype.c is needed by isspace() of linux/ctype.h.
* While both lib/ctype.c and lib/cmdline.c will bring EXPORT_SYMBOL
* which is meaningless and will cause compiling error in some cases.
- * So do not include linux/export.h and define EXPORT_SYMBOL(sym)
- * as empty.
*/
-#define _LINUX_EXPORT_H
-#define EXPORT_SYMBOL(sym)
+#define __DISABLE_EXPORTS
#include "misc.h"
#include "error.h"
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 7b3ba40f0745..896a882c89f4 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -20,7 +20,8 @@ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
-D__NO_FORTIFY \
$(call cc-option,-ffreestanding) \
- $(call cc-option,-fno-stack-protector)
+ $(call cc-option,-fno-stack-protector) \
+ -D__DISABLE_EXPORTS
GCOV_PROFILE := n
KASAN_SANITIZE := n
diff --git a/include/linux/export.h b/include/linux/export.h
index 1a1dfdb2a5c6..25005b55b079 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -72,7 +72,16 @@ extern struct module __this_module;
__attribute__((section("___ksymtab" sec "+" #sym), used)) \
= { (unsigned long)&sym, __kstrtab_##sym }
-#if defined(__KSYM_DEPS__)
+#if defined(__DISABLE_EXPORTS)
+
+/*
+ * Allow symbol exports to be disabled completely so that C code may
+ * be reused in other execution contexts such as the UEFI stub or the
+ * decompressor.
+ */
+#define __EXPORT_SYMBOL(sym, sec)
+
+#elif defined(__KSYM_DEPS__)
/*
* For fine grained build dependencies, we want to tell the build system
--
2.15.1
^ permalink raw reply related
* [PATCH v8 1/6] arch: enable relative relocations for arm64, power and x86
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org>
Before updating certain subsystems to use place relative 32-bit
relocations in special sections, to save space and reduce the
number of absolute relocations that need to be processed at runtime
by relocatable kernels, introduce the Kconfig symbol and define it
for some architectures that should be able to support and benefit
from it.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: x86@kernel.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/Kconfig | 10 ++++++++++
arch/arm64/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/x86/Kconfig | 1 +
4 files changed, 13 insertions(+)
diff --git a/arch/Kconfig b/arch/Kconfig
index 76c0b54443b1..4e624f75823a 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -975,4 +975,14 @@ config REFCOUNT_FULL
against various use-after-free conditions that can be used in
security flaw exploits.
+config HAVE_ARCH_PREL32_RELOCATIONS
+ bool
+ help
+ May be selected by an architecture if it supports place-relative
+ 32-bit relocations, both in the toolchain and in the module loader,
+ in which case relative references can be used in special sections
+ for PCI fixup, initcalls etc which are only half the size on 64 bit
+ architectures, and don't require runtime relocation on relocatable
+ kernels.
+
source "kernel/gcov/Kconfig"
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7381eeb7ef8e..7c543667703e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -91,6 +91,7 @@ config ARM64
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
+ select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_THREAD_STRUCT_WHITELIST
select HAVE_ARCH_TRACEHOOK
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 73ce5dd07642..21d5ad1608d8 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -181,6 +181,7 @@ config PPC
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
+ select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_CBPF_JIT if !PPC64
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c1236b187824..1c6e2ddd2fdc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -117,6 +117,7 @@ config X86
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
+ select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_THREAD_STRUCT_WHITELIST
select HAVE_ARCH_TRACEHOOK
--
2.15.1
^ permalink raw reply related
* [PATCH v8 0/6] add support for relative references in special sections
From: Ard Biesheuvel @ 2018-03-11 12:38 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Ard Biesheuvel, Arnd Bergmann, Kees Cook, Will Deacon,
Michael Ellerman, Thomas Garnier, Thomas Gleixner,
Serge E. Hallyn, Bjorn Helgaas, Benjamin Herrenschmidt,
Russell King, Paul Mackerras, Catalin Marinas, Petr Mladek,
Ingo Molnar, James Morris, Andrew Morton, Nicolas Pitre,
Josh Poimboeuf, Steven Rostedt, Sergey Senozhatsky,
Linus Torvalds, Jessica Yu, linux-kernel, linuxppc-dev, x86
This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references. This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata
for these sections in relocatable kernels (e.g., for KASLR) that needs
to be fixed up at boot time. On arm64, this reduces the vmlinux footprint
of such a reference by 8x (8 byte absolute reference + 24 byte RELA entry
vs 4 byte relative reference)
Patch #3 was sent out before as a single patch. This series supersedes
the previous submission. This version makes relative ksymtab entries
dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather
than trying to infer from kbuild test robot replies for which architectures
it should be blacklisted.
Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS,
and sets it for the main architectures that are expected to benefit the
most from this feature, i.e., 64-bit architectures or ones that use
runtime relocations.
Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of
ksymtab/kcrctab sections in decompressor and EFI stub objects when
rebuilding existing C files to run in a different context.
Patches #4 - #6 implement relative references for initcalls, PCI fixups
and tracepoints, respectively, all of which produce sections with order
~1000 entries on an arm64 defconfig kernel with tracing enabled. This
means we save about 28 KB of vmlinux space for each of these patches.
[From the v7 series blurb, which included the jump_label patches as well]:
For the arm64 kernel, all patches combined reduce the memory footprint of
vmlinux by about 1.3 MB (using a config copied from Ubuntu that has KASLR
enabled), of which ~1 MB is the size reduction of the RELA section in .init,
and the remaining 300 KB is reduction of .text/.data.
Branch:
git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git relative-special-sections-v8
Changes since v7:
- dropped the jump_label patches, these will be revisited in a separate series
- reorder __DISABLE_EXPORTS with __KSYM_DEPS__ check in #2
- use offset_to_ptr() helper function to abstract the relative pointer
conversion [int *off -> (ulong)off + *off] (#3 - #6)
- rebase onto v4.16-rc3
Changes since v6:
- drop S390 from patch #1 introducing HAVE_ARCH_PREL32_RELOCATIONS: kbuild
robot threw me some s390 curveballs, and given that s390 does not define
CONFIG_RELOCATABLE in the first place, it does not benefit as much from
relative references as arm64, x86 and power do
- add patch to allow symbol exports to be disabled at compilation unit
granularity (#2)
- get rid of arm64 vmlinux.lds.S hunk to ensure code generated by __ADDRESSABLE
gets discarded from the EFI stub - it is no longer needed after adding #2 (#1)
- change _ADDRESSABLE() to emit a data reference, not a code reference - this
is another simplification made possible by patch #2 (#3)
- add Steven's ack to #6
- split x86 jump_label patch into two (#9, #10)
Changes since v5:
- add missing jump_label prototypes to s390 jump_label.h (#6)
- fix inverted condition in call to jump_entry_is_module_init() (#6)
Changes since v4:
- add patches to convert x86 and arm64 to use relative references for jump
tables (#6 - #8)
- rename PCI patch and add Bjorn's ack (#4)
- rebase onto v4.15-rc5
Changes since v3:
- fix module unload issue in patch #5 reported by Jessica, by reusing the
updated routine for_each_tracepoint_range() for the quiescent check at
module unload time; this requires this routine to be moved before
tracepoint_module_going() in kernel/tracepoint.c
- add Jessica's ack to #2
- rebase onto v4.14-rc1
Changes since v2:
- Revert my slightly misguided attempt to appease checkpatch, which resulted
in needless churn and worse code. This v3 is based on v1 with a few tweaks
that were actually reasonable checkpatch warnings: unnecessary braces (as
pointed out by Ingo) and other minor whitespace misdemeanors.
Changes since v1:
- Remove checkpatch errors to the extent feasible: in some cases, this
involves moving extern declarations into C files, and switching to
struct definitions rather than typedefs. Some errors are impossible
to fix: please find the remaining ones after the diffstat.
- Used 'int' instead if 'signed int' for the various offset fields: there
is no ambiguity between architectures regarding its signedness (unlike
'char')
- Refactor the different patches to be more uniform in the way they define
the section entry type and accessors in the .h file, and avoid the need to
add #ifdefs to the C code.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: x86@kernel.org
Ard Biesheuvel (6):
arch: enable relative relocations for arm64, power and x86
module: allow symbol exports to be disabled
module: use relative references for __ksymtab entries
init: allow initcall tables to be emitted using relative references
PCI: Add support for relative addressing in quirk tables
kernel: tracepoints: add support for relative references
arch/Kconfig | 10 ++++
arch/arm64/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/x86/Kconfig | 1 +
arch/x86/boot/compressed/kaslr.c | 5 +-
arch/x86/include/asm/Kbuild | 1 +
arch/x86/include/asm/export.h | 5 --
drivers/firmware/efi/libstub/Makefile | 3 +-
drivers/pci/quirks.c | 12 +++--
include/asm-generic/export.h | 12 ++++-
include/linux/compiler.h | 19 +++++++
include/linux/export.h | 57 +++++++++++++++-----
include/linux/init.h | 44 +++++++++++----
include/linux/pci.h | 20 +++++++
include/linux/tracepoint.h | 19 +++++--
init/main.c | 32 +++++------
kernel/module.c | 32 ++++++++---
kernel/printk/printk.c | 4 +-
kernel/tracepoint.c | 49 +++++++++--------
security/security.c | 4 +-
20 files changed, 240 insertions(+), 91 deletions(-)
delete mode 100644 arch/x86/include/asm/export.h
--
2.15.1
^ permalink raw reply
* [PATCH] powerpc: Use common error handling code in setup_new_fdt()
From: SF Markus Elfring @ 2018-03-11 8:16 UTC (permalink / raw)
To: linuxppc-dev, Benjamin Herrenschmidt, Borislav Petkov,
Brijesh Singh, Josh Sklar, Kees Cook, Michael Ellerman,
Paul Mackerras, Thiago Jung Bauermann, Thomas Gleixner,
Tom Lendacky
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 11 Mar 2018 09:03:42 +0100
Add a jump target so that a bit of exception handling can be better reused
at the end of this function.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
arch/powerpc/kernel/machine_kexec_file_64.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
index e4395f937d63..90c6004c2eec 100644
--- a/arch/powerpc/kernel/machine_kexec_file_64.c
+++ b/arch/powerpc/kernel/machine_kexec_file_64.c
@@ -302,18 +302,14 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
ret = fdt_setprop_u64(fdt, chosen_node,
"linux,initrd-start",
initrd_load_addr);
- if (ret < 0) {
- pr_err("Error setting up the new device tree.\n");
- return -EINVAL;
- }
+ if (ret < 0)
+ goto report_setup_failure;
/* initrd-end is the first address after the initrd image. */
ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
initrd_load_addr + initrd_len);
- if (ret < 0) {
- pr_err("Error setting up the new device tree.\n");
- return -EINVAL;
- }
+ if (ret < 0)
+ goto report_setup_failure;
ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
if (ret) {
@@ -325,10 +321,8 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
if (cmdline != NULL) {
ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
- if (ret < 0) {
- pr_err("Error setting up the new device tree.\n");
- return -EINVAL;
- }
+ if (ret < 0)
+ goto report_setup_failure;
} else {
ret = fdt_delprop(fdt, chosen_node, "bootargs");
if (ret && ret != -FDT_ERR_NOTFOUND) {
@@ -344,10 +338,12 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
}
ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
- if (ret) {
- pr_err("Error setting up the new device tree.\n");
- return -EINVAL;
- }
+ if (ret)
+ goto report_setup_failure;
return 0;
+
+report_setup_failure:
+ pr_err("Error setting up the new device tree.\n");
+ return -EINVAL;
}
--
2.16.2
^ permalink raw reply related
* Re: [PATCH] powerpc/mm: Fix section mismatch warning in stop_machine_change_mapping()
From: Balbir Singh @ 2018-03-11 6:23 UTC (permalink / raw)
To: Mauricio Faria de Oliveira
Cc: open list:LINUX FOR POWERPC (32-BIT AND 64-BIT), Michael Ellerman,
Aneesh Kumar KV, Nicholas Piggin
In-Reply-To: <1520628358-1762-1-git-send-email-mauricfo@linux.vnet.ibm.com>
On Sat, Mar 10, 2018 at 7:45 AM, Mauricio Faria de Oliveira
<mauricfo@linux.vnet.ibm.com> wrote:
> Fix the warning messages for stop_machine_change_mapping(), and a number
> of other affected functions in its call chain.
>
> All modified functions are under CONFIG_MEMORY_HOTPLUG, so __meminit
> is okay (keeps them / does not discard them).
>
> Boot-tested on powernv/power9/radix-mmu and pseries/power8/hash-mmu.
>
> $ make -j$(nproc) CONFIG_DEBUG_SECTION_MISMATCH=y vmlinux
> ...
> MODPOST vmlinux.o
> WARNING: vmlinux.o(.text+0x6b130): Section mismatch in reference from the function stop_machine_change_mapping() to the function .meminit.text:create_physical_mapping()
> The function stop_machine_change_mapping() references
> the function __meminit create_physical_mapping().
> This is often because stop_machine_change_mapping lacks a __meminit
> annotation or the annotation of create_physical_mapping is wrong.
>
> WARNING: vmlinux.o(.text+0x6b13c): Section mismatch in reference from the function stop_machine_change_mapping() to the function .meminit.text:create_physical_mapping()
> The function stop_machine_change_mapping() references
> the function __meminit create_physical_mapping().
> This is often because stop_machine_change_mapping lacks a __meminit
> annotation or the annotation of create_physical_mapping is wrong.
> ...
>
> Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
> ---
Looks reasonable, I'd recommend trying to compile with MEMORY_HOTPLUG
and MEMORY_HOTREMOVE enabled/disabled as well
Acked-by: Balbir Singh <bsingharora@gmail.com>
Balbir Singh.
^ permalink raw reply
* Re: [PATCH 4.14 1/4] powerpc/mm/slice: Remove intermediate bitmap copy
From: Greg Kroah-Hartman @ 2018-03-10 19:47 UTC (permalink / raw)
To: christophe leroy; +Cc: stable, linux-kernel, linuxppc-dev
In-Reply-To: <84cf5fef-a940-cb2a-431e-5a550f725c4f@c-s.fr>
On Sat, Mar 10, 2018 at 05:14:22PM +0100, christophe leroy wrote:
>
>
> Le 10/03/2018 à 15:52, Greg Kroah-Hartman a écrit :
> > On Sat, Mar 10, 2018 at 08:27:54AM +0100, christophe leroy wrote:
> > >
> > >
> > > Le 10/03/2018 à 01:10, Greg Kroah-Hartman a écrit :
> > > > On Fri, Mar 09, 2018 at 04:48:59PM +0100, Christophe Leroy wrote:
> > > > > Upstream 326691ad4f179e6edc7eb1271e618dd673e4736d
> > > >
> > > > There is no such git commit id in Linus's tree :(
> > > >
> > > > Please fix up and resend the series.
> > >
> > > I checked again, it is there
> > >
> > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/powerpc/mm/slice.c?h=next-20180309&id=326691ad4f179e6edc7eb1271e618dd673e4736d
> >
> > That is linux-next, which has everything and the kitchen sink. It is
> > not Linus's tree. Please wait for these things to be merged into
> > Linus's tree before asking for the to be merged into the stable tree.
> > That's a requirement.
> >
>
> Oops, sorry, I thought everything on kernel.org was official.
That would be a whole lot of "official" :)
Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for what the rules are here, if you haven't already.
> Once it is in, do I resend the patches or do I just ping you ?
You would need to resend the patches (if they need backporting
manually), or just send a list of the git commit ids that are needed to
be applied (usually easier.)
Also, why were these patches not tagged with the stable tag to start
with? That way they would be automatically included in the stable tree
when they hit Linus's tree.
thanks,
greg k-h
^ permalink raw reply
* Re: [PATCH 03/21] powerpc: Mark the variable earlycon_acpi_spcr_enable maybe_unused
From: Mathieu Malaterre @ 2018-03-10 18:08 UTC (permalink / raw)
To: Michael Ellerman
Cc: Benjamin Herrenschmidt, Paul Mackerras, Jiri Slaby, linuxppc-dev,
LKML
In-Reply-To: <87po4kglgv.fsf@concordia.ellerman.id.au>
On Sun, Mar 4, 2018 at 11:54 AM, Michael Ellerman <mpe@ellerman.id.au> wrot=
e:
> Mathieu Malaterre <malat@debian.org> writes:
>
>> Re-use the object-like macro EARLYCON_USED_OR_UNUSED to mark
>> `earlycon_acpi_spcr_enable` as maybe_unused.
>>
>> Fix the following warning (treated as error in W=3D1)
>>
>> CC arch/powerpc/kernel/setup-common.o
>> In file included from ./include/linux/serial_8250.h:14:0,
>> from arch/powerpc/kernel/setup-common.c:33:
>> ./include/linux/serial_core.h:382:19: error: =E2=80=98earlycon_acpi_spcr=
_enable=E2=80=99 defined but not used [-Werror=3Dunused-const-variable=3D]
>> static const bool earlycon_acpi_spcr_enable;
>> ^~~~~~~~~~~~~~~~~~~~~~~~~
>> cc1: all warnings being treated as errors
>>
>> Signed-off-by: Mathieu Malaterre <malat@debian.org>
>> ---
>> include/linux/serial_core.h | 1 +
>
> I can't take this one as that's not a file I maintain.
>
> The script says:
>
> $ ./scripts/get_maintainer.pl include/linux/serial_core.h
> gregkh@linuxfoundation.org
> jslaby@suse.com
> linux-kernel@vger.kernel.org
>
>
> Can you resend it to them?
Ah right, thanks.
>
>> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
>> index b32df49a3bd5..4d14ecd7dbe8 100644
>> --- a/include/linux/serial_core.h
>> +++ b/include/linux/serial_core.h
>> @@ -379,6 +379,7 @@ extern int of_setup_earlycon(const struct earlycon_i=
d *match,
>> extern bool earlycon_acpi_spcr_enable __initdata;
>> int setup_earlycon(char *buf);
>> #else
>> +EARLYCON_USED_OR_UNUSED
>> static const bool earlycon_acpi_spcr_enable;
>
> The macro eventually turns into an __attribute__, which I think is
> typically placed after the variable, so eg:
>
> static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
>
Indeed makes it more consistent with style. Thanks!
> cheers
>
>> static inline int setup_earlycon(char *buf) { return 0; }
>> #endif
>> --
>> 2.11.0
^ permalink raw reply
* Re: [PATCH 4.14 1/4] powerpc/mm/slice: Remove intermediate bitmap copy
From: christophe leroy @ 2018-03-10 16:14 UTC (permalink / raw)
To: Greg Kroah-Hartman; +Cc: stable, linux-kernel, linuxppc-dev
In-Reply-To: <20180310145258.GA6874@kroah.com>
Le 10/03/2018 à 15:52, Greg Kroah-Hartman a écrit :
> On Sat, Mar 10, 2018 at 08:27:54AM +0100, christophe leroy wrote:
>>
>>
>> Le 10/03/2018 à 01:10, Greg Kroah-Hartman a écrit :
>>> On Fri, Mar 09, 2018 at 04:48:59PM +0100, Christophe Leroy wrote:
>>>> Upstream 326691ad4f179e6edc7eb1271e618dd673e4736d
>>>
>>> There is no such git commit id in Linus's tree :(
>>>
>>> Please fix up and resend the series.
>>
>> I checked again, it is there
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/powerpc/mm/slice.c?h=next-20180309&id=326691ad4f179e6edc7eb1271e618dd673e4736d
>
> That is linux-next, which has everything and the kitchen sink. It is
> not Linus's tree. Please wait for these things to be merged into
> Linus's tree before asking for the to be merged into the stable tree.
> That's a requirement.
>
Oops, sorry, I thought everything on kernel.org was official.
Once it is in, do I resend the patches or do I just ping you ?
Thanks
Christophe
---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus
^ permalink raw reply
* Re: [PATCH 4.14 1/4] powerpc/mm/slice: Remove intermediate bitmap copy
From: Greg Kroah-Hartman @ 2018-03-10 14:52 UTC (permalink / raw)
To: christophe leroy; +Cc: stable, linux-kernel, linuxppc-dev
In-Reply-To: <39af0017-6a9c-a032-8167-40b5f30840f8@c-s.fr>
On Sat, Mar 10, 2018 at 08:27:54AM +0100, christophe leroy wrote:
>
>
> Le 10/03/2018 à 01:10, Greg Kroah-Hartman a écrit :
> > On Fri, Mar 09, 2018 at 04:48:59PM +0100, Christophe Leroy wrote:
> > > Upstream 326691ad4f179e6edc7eb1271e618dd673e4736d
> >
> > There is no such git commit id in Linus's tree :(
> >
> > Please fix up and resend the series.
>
> I checked again, it is there
>
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/powerpc/mm/slice.c?h=next-20180309&id=326691ad4f179e6edc7eb1271e618dd673e4736d
That is linux-next, which has everything and the kitchen sink. It is
not Linus's tree. Please wait for these things to be merged into
Linus's tree before asking for the to be merged into the stable tree.
That's a requirement.
thanks,
greg k-h
^ permalink raw reply
* Re: [PATCH 4.14 1/4] powerpc/mm/slice: Remove intermediate bitmap copy
From: christophe leroy @ 2018-03-10 7:27 UTC (permalink / raw)
To: Greg Kroah-Hartman; +Cc: stable, linux-kernel, linuxppc-dev
In-Reply-To: <20180310001043.GD13963@kroah.com>
Le 10/03/2018 à 01:10, Greg Kroah-Hartman a écrit :
> On Fri, Mar 09, 2018 at 04:48:59PM +0100, Christophe Leroy wrote:
>> Upstream 326691ad4f179e6edc7eb1271e618dd673e4736d
>
> There is no such git commit id in Linus's tree :(
>
> Please fix up and resend the series.
I checked again, it is there
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/powerpc/mm/slice.c?h=next-20180309&id=326691ad4f179e6edc7eb1271e618dd673e4736d
The id seems to be exactly the same.
Christophe
>
> thanks,
>
> greg k-h
>
---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus
^ permalink raw reply
* Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0
From: Dave Hansen @ 2018-03-10 6:50 UTC (permalink / raw)
To: Ram Pai
Cc: mpe, mingo, akpm, linuxppc-dev, linux-mm, x86, linux-arch,
linux-kernel, benh, paulus, khandual, aneesh.kumar, bsingharora,
hbabu, mhocko, bauerman, ebiederm, corbet, arnd, fweimer,
msuchanek, Ulrich.Weigand
In-Reply-To: <20180310055544.GU1060@ram.oc3035372033.ibm.com>
On 03/09/2018 09:55 PM, Ram Pai wrote:
> On Fri, Mar 09, 2018 at 02:40:32PM -0800, Dave Hansen wrote:
>> On 03/09/2018 12:12 AM, Ram Pai wrote:
>>> Once an address range is associated with an allocated pkey, it cannot be
>>> reverted back to key-0. There is no valid reason for the above behavior. On
>>> the contrary applications need the ability to do so.
>> Why don't we just set pkey 0 to be allocated in the allocation bitmap by
>> default?
> ok. that will make it allocatable. But it will not be associatable,
> given the bug in the current code. And what will be the
> default key associated with a pte? zero? or something else?
I'm just saying that I think we should try to keep from making it
special as much as possible.
Let's fix the bug that keeps it from being associatable.
^ permalink raw reply
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