* [PATCH] RISC-V: Handle R_RISCV_32 in modules
@ 2018-06-07 10:27 ` Andreas Schwab
0 siblings, 0 replies; 8+ messages in thread
From: Andreas Schwab @ 2018-06-07 10:27 UTC (permalink / raw)
To: linux-riscv
With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
__kcrctab section.
Signed-off-by: Andreas Schwab <schwab@suse.de>
---
arch/riscv/kernel/module.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 5dddba301d..1d5e9b934b 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -17,6 +17,17 @@
#include <linux/errno.h>
#include <linux/moduleloader.h>
+static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v != (u32)v) {
+ pr_err("%s: value %016llx out of range for 32-bit field\n",
+ me->name, v);
+ return -EINVAL;
+ }
+ *location = v;
+ return 0;
+}
+
static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
{
*(u64 *)location = v;
@@ -265,6 +276,7 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
Elf_Addr v) = {
+ [R_RISCV_32] = apply_r_riscv_32_rela,
[R_RISCV_64] = apply_r_riscv_64_rela,
[R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
[R_RISCV_JAL] = apply_r_riscv_jal_rela,
--
2.17.1
--
Andreas Schwab, SUSE Labs, schwab at suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH] RISC-V: Handle R_RISCV_32 in modules
@ 2018-06-07 10:27 ` Andreas Schwab
0 siblings, 0 replies; 8+ messages in thread
From: Andreas Schwab @ 2018-06-07 10:27 UTC (permalink / raw)
To: linux-riscv; +Cc: linux-kernel
With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
__kcrctab section.
Signed-off-by: Andreas Schwab <schwab@suse.de>
---
arch/riscv/kernel/module.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 5dddba301d..1d5e9b934b 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -17,6 +17,17 @@
#include <linux/errno.h>
#include <linux/moduleloader.h>
+static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v != (u32)v) {
+ pr_err("%s: value %016llx out of range for 32-bit field\n",
+ me->name, v);
+ return -EINVAL;
+ }
+ *location = v;
+ return 0;
+}
+
static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
{
*(u64 *)location = v;
@@ -265,6 +276,7 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
Elf_Addr v) = {
+ [R_RISCV_32] = apply_r_riscv_32_rela,
[R_RISCV_64] = apply_r_riscv_64_rela,
[R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
[R_RISCV_JAL] = apply_r_riscv_jal_rela,
--
2.17.1
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH] RISC-V: Handle R_RISCV_32 in modules
2018-06-07 10:27 ` Andreas Schwab
@ 2018-06-08 22:33 ` Palmer Dabbelt
-1 siblings, 0 replies; 8+ messages in thread
From: Palmer Dabbelt @ 2018-06-08 22:33 UTC (permalink / raw)
To: linux-riscv
On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab at suse.de wrote:
> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
> __kcrctab section.
>
> Signed-off-by: Andreas Schwab <schwab@suse.de>
> ---
> arch/riscv/kernel/module.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
> index 5dddba301d..1d5e9b934b 100644
> --- a/arch/riscv/kernel/module.c
> +++ b/arch/riscv/kernel/module.c
> @@ -17,6 +17,17 @@
> #include <linux/errno.h>
> #include <linux/moduleloader.h>
>
> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + if (v != (u32)v) {
My worry with this kind of check is that it relies on some sort of undefined
behavior in C and that at some point in the future GCC will just go decide the
check can never fail. I checked and GCC doesn't elide these checks now, so I
might be wrong.
Is this defined to do what it looks like it's doing?
> + pr_err("%s: value %016llx out of range for 32-bit field\n",
> + me->name, v);
> + return -EINVAL;
> + }
> + *location = v;
> + return 0;
> +}
> +
> static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
> {
> *(u64 *)location = v;
> @@ -265,6 +276,7 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>
> static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
> Elf_Addr v) = {
> + [R_RISCV_32] = apply_r_riscv_32_rela,
> [R_RISCV_64] = apply_r_riscv_64_rela,
> [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
> [R_RISCV_JAL] = apply_r_riscv_jal_rela,
Thanks!
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] RISC-V: Handle R_RISCV_32 in modules
@ 2018-06-08 22:33 ` Palmer Dabbelt
0 siblings, 0 replies; 8+ messages in thread
From: Palmer Dabbelt @ 2018-06-08 22:33 UTC (permalink / raw)
To: schwab; +Cc: linux-riscv, linux-kernel
On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab@suse.de wrote:
> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
> __kcrctab section.
>
> Signed-off-by: Andreas Schwab <schwab@suse.de>
> ---
> arch/riscv/kernel/module.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
> index 5dddba301d..1d5e9b934b 100644
> --- a/arch/riscv/kernel/module.c
> +++ b/arch/riscv/kernel/module.c
> @@ -17,6 +17,17 @@
> #include <linux/errno.h>
> #include <linux/moduleloader.h>
>
> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + if (v != (u32)v) {
My worry with this kind of check is that it relies on some sort of undefined
behavior in C and that at some point in the future GCC will just go decide the
check can never fail. I checked and GCC doesn't elide these checks now, so I
might be wrong.
Is this defined to do what it looks like it's doing?
> + pr_err("%s: value %016llx out of range for 32-bit field\n",
> + me->name, v);
> + return -EINVAL;
> + }
> + *location = v;
> + return 0;
> +}
> +
> static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
> {
> *(u64 *)location = v;
> @@ -265,6 +276,7 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>
> static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
> Elf_Addr v) = {
> + [R_RISCV_32] = apply_r_riscv_32_rela,
> [R_RISCV_64] = apply_r_riscv_64_rela,
> [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
> [R_RISCV_JAL] = apply_r_riscv_jal_rela,
Thanks!
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH] RISC-V: Handle R_RISCV_32 in modules
2018-06-08 22:33 ` Palmer Dabbelt
@ 2018-06-11 7:54 ` Andreas Schwab
-1 siblings, 0 replies; 8+ messages in thread
From: Andreas Schwab @ 2018-06-11 7:54 UTC (permalink / raw)
To: linux-riscv
On Jun 08 2018, Palmer Dabbelt <palmer@sifive.com> wrote:
> On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab at suse.de wrote:
>> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
>> __kcrctab section.
>>
>> Signed-off-by: Andreas Schwab <schwab@suse.de>
>> ---
>> arch/riscv/kernel/module.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
>> index 5dddba301d..1d5e9b934b 100644
>> --- a/arch/riscv/kernel/module.c
>> +++ b/arch/riscv/kernel/module.c
>> @@ -17,6 +17,17 @@
>> #include <linux/errno.h>
>> #include <linux/moduleloader.h>
>>
>> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
>> +{
>> + if (v != (u32)v) {
>
> My worry with this kind of check is that it relies on some sort of
> undefined behavior in C and that at some point in the future GCC will just
> go decide the check can never fail. I checked and GCC doesn't elide these
> checks now, so I might be wrong.
>
> Is this defined to do what it looks like it's doing?
This is unsigned arithmetic, thus fully defined.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab at suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] RISC-V: Handle R_RISCV_32 in modules
@ 2018-06-11 7:54 ` Andreas Schwab
0 siblings, 0 replies; 8+ messages in thread
From: Andreas Schwab @ 2018-06-11 7:54 UTC (permalink / raw)
To: Palmer Dabbelt; +Cc: linux-riscv, linux-kernel
On Jun 08 2018, Palmer Dabbelt <palmer@sifive.com> wrote:
> On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab@suse.de wrote:
>> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
>> __kcrctab section.
>>
>> Signed-off-by: Andreas Schwab <schwab@suse.de>
>> ---
>> arch/riscv/kernel/module.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
>> index 5dddba301d..1d5e9b934b 100644
>> --- a/arch/riscv/kernel/module.c
>> +++ b/arch/riscv/kernel/module.c
>> @@ -17,6 +17,17 @@
>> #include <linux/errno.h>
>> #include <linux/moduleloader.h>
>>
>> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
>> +{
>> + if (v != (u32)v) {
>
> My worry with this kind of check is that it relies on some sort of
> undefined behavior in C and that at some point in the future GCC will just
> go decide the check can never fail. I checked and GCC doesn't elide these
> checks now, so I might be wrong.
>
> Is this defined to do what it looks like it's doing?
This is unsigned arithmetic, thus fully defined.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH] RISC-V: Handle R_RISCV_32 in modules
2018-06-11 7:54 ` Andreas Schwab
@ 2018-06-11 20:53 ` Palmer Dabbelt
-1 siblings, 0 replies; 8+ messages in thread
From: Palmer Dabbelt @ 2018-06-11 20:53 UTC (permalink / raw)
To: linux-riscv
On Mon, 11 Jun 2018 00:54:00 PDT (-0700), schwab at suse.de wrote:
> On Jun 08 2018, Palmer Dabbelt <palmer@sifive.com> wrote:
>
>> On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab at suse.de wrote:
>>> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
>>> __kcrctab section.
>>>
>>> Signed-off-by: Andreas Schwab <schwab@suse.de>
>>> ---
>>> arch/riscv/kernel/module.c | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
>>> index 5dddba301d..1d5e9b934b 100644
>>> --- a/arch/riscv/kernel/module.c
>>> +++ b/arch/riscv/kernel/module.c
>>> @@ -17,6 +17,17 @@
>>> #include <linux/errno.h>
>>> #include <linux/moduleloader.h>
>>>
>>> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
>>> +{
>>> + if (v != (u32)v) {
>>
>> My worry with this kind of check is that it relies on some sort of
>> undefined behavior in C and that at some point in the future GCC will just
>> go decide the check can never fail. I checked and GCC doesn't elide these
>> checks now, so I might be wrong.
>>
>> Is this defined to do what it looks like it's doing?
>
> This is unsigned arithmetic, thus fully defined.
Great, thanks! I guess I'm just a bit paranoid :)
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] RISC-V: Handle R_RISCV_32 in modules
@ 2018-06-11 20:53 ` Palmer Dabbelt
0 siblings, 0 replies; 8+ messages in thread
From: Palmer Dabbelt @ 2018-06-11 20:53 UTC (permalink / raw)
To: schwab; +Cc: linux-riscv, linux-kernel
On Mon, 11 Jun 2018 00:54:00 PDT (-0700), schwab@suse.de wrote:
> On Jun 08 2018, Palmer Dabbelt <palmer@sifive.com> wrote:
>
>> On Thu, 07 Jun 2018 03:27:27 PDT (-0700), schwab@suse.de wrote:
>>> With CONFIG_MODVERSIONS=y the R_RISCV_32 relocation is used by the
>>> __kcrctab section.
>>>
>>> Signed-off-by: Andreas Schwab <schwab@suse.de>
>>> ---
>>> arch/riscv/kernel/module.c | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
>>> index 5dddba301d..1d5e9b934b 100644
>>> --- a/arch/riscv/kernel/module.c
>>> +++ b/arch/riscv/kernel/module.c
>>> @@ -17,6 +17,17 @@
>>> #include <linux/errno.h>
>>> #include <linux/moduleloader.h>
>>>
>>> +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
>>> +{
>>> + if (v != (u32)v) {
>>
>> My worry with this kind of check is that it relies on some sort of
>> undefined behavior in C and that at some point in the future GCC will just
>> go decide the check can never fail. I checked and GCC doesn't elide these
>> checks now, so I might be wrong.
>>
>> Is this defined to do what it looks like it's doing?
>
> This is unsigned arithmetic, thus fully defined.
Great, thanks! I guess I'm just a bit paranoid :)
^ permalink raw reply [flat|nested] 8+ messages in thread
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2018-06-07 10:27 [PATCH] RISC-V: Handle R_RISCV_32 in modules Andreas Schwab
2018-06-07 10:27 ` Andreas Schwab
2018-06-08 22:33 ` Palmer Dabbelt
2018-06-08 22:33 ` Palmer Dabbelt
2018-06-11 7:54 ` Andreas Schwab
2018-06-11 7:54 ` Andreas Schwab
2018-06-11 20:53 ` Palmer Dabbelt
2018-06-11 20:53 ` Palmer Dabbelt
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