* [PATCH] um: Allow building and running on older hosts
@ 2017-05-24 1:08 Florian Fainelli
2017-05-24 7:01 ` Richard Weinberger
0 siblings, 1 reply; 4+ messages in thread
From: Florian Fainelli @ 2017-05-24 1:08 UTC (permalink / raw)
To: linux-kernel
Cc: elicooper, Florian Fainelli, Jeff Dike, Richard Weinberger,
Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT,
open list:USER-MODE LINUX, , open list:USER-MODE LINUX
Commit a78ff1112263 ("um: add extended processor state save/restore
support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
YMM registers") forced the use of the x86 FP _xstate and
PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
build UML nor run it anymore with these two commits applied because we
don't have definitions for struct _xstate nor these two ptrace requests.
We can determine at build time which fp context structure to check
against, just like we can keep using the old i387 fp save/restore if
PTRACE_GETRESET/SETREGSET are not defined.
Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
arch/x86/um/os-Linux/registers.c | 13 +++++++++----
arch/x86/um/user-offsets.c | 4 ++++
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
index 00f54a91bb4b..502bd642e5c2 100644
--- a/arch/x86/um/os-Linux/registers.c
+++ b/arch/x86/um/os-Linux/registers.c
@@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
int save_fp_registers(int pid, unsigned long *fp_regs)
{
- struct iovec iov;
-
if (have_xstate_support) {
+#ifdef PTRACE_GETREGSET
+ struct iovec iov;
iov.iov_base = fp_regs;
iov.iov_len = sizeof(struct _xstate);
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
+#endif
return 0;
} else {
return save_i387_registers(pid, fp_regs);
@@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long *fp_regs)
int restore_fp_registers(int pid, unsigned long *fp_regs)
{
- struct iovec iov;
-
if (have_xstate_support) {
+#ifdef PTRACE_SETREGSET
+ struct iovec iov;
+
iov.iov_base = fp_regs;
iov.iov_len = sizeof(struct _xstate);
if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
+#endif
return 0;
} else {
return restore_i387_registers(pid, fp_regs);
@@ -127,8 +130,10 @@ void arch_init_registers(int pid)
iov.iov_base = &fp_regs;
iov.iov_len = sizeof(struct _xstate);
+#ifdef PTRACE_GETREGSET
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
have_xstate_support = 1;
+#endif
}
#endif
diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
index cb3c22370cf5..8af0fb5d2780 100644
--- a/arch/x86/um/user-offsets.c
+++ b/arch/x86/um/user-offsets.c
@@ -50,7 +50,11 @@ void foo(void)
DEFINE(HOST_GS, GS);
DEFINE(HOST_ORIG_AX, ORIG_EAX);
#else
+#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
+#else
+ DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
+#endif
DEFINE_LONGS(HOST_BX, RBX);
DEFINE_LONGS(HOST_CX, RCX);
DEFINE_LONGS(HOST_DI, RDI);
--
2.12.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] um: Allow building and running on older hosts
2017-05-24 1:08 [PATCH] um: Allow building and running on older hosts Florian Fainelli
@ 2017-05-24 7:01 ` Richard Weinberger
2017-05-24 9:03 ` Thomas Meyer
0 siblings, 1 reply; 4+ messages in thread
From: Richard Weinberger @ 2017-05-24 7:01 UTC (permalink / raw)
To: Florian Fainelli, linux-kernel
Cc: elicooper, Jeff Dike, Thomas Gleixner, Ingo Molnar,
H. Peter Anvin, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
open list:USER-MODE LINUX (UML), open list:USER-MODE LINUX (UML),
Thomas Meyer
CC'ing Thomas. We is also facing issues with these commits.
Am 24.05.2017 um 03:08 schrieb Florian Fainelli:
> Commit a78ff1112263 ("um: add extended processor state save/restore
> support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
> YMM registers") forced the use of the x86 FP _xstate and
> PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
> build UML nor run it anymore with these two commits applied because we
> don't have definitions for struct _xstate nor these two ptrace requests.
>
> We can determine at build time which fp context structure to check
> against, just like we can keep using the old i387 fp save/restore if
> PTRACE_GETRESET/SETREGSET are not defined.
>
> Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
> Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> arch/x86/um/os-Linux/registers.c | 13 +++++++++----
> arch/x86/um/user-offsets.c | 4 ++++
> 2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
> index 00f54a91bb4b..502bd642e5c2 100644
> --- a/arch/x86/um/os-Linux/registers.c
> +++ b/arch/x86/um/os-Linux/registers.c
> @@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
>
> int save_fp_registers(int pid, unsigned long *fp_regs)
> {
> - struct iovec iov;
> -
> if (have_xstate_support) {
> +#ifdef PTRACE_GETREGSET
> + struct iovec iov;
> iov.iov_base = fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
> return -errno;
> +#endif
> return 0;
> } else {
> return save_i387_registers(pid, fp_regs);
> @@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long *fp_regs)
>
> int restore_fp_registers(int pid, unsigned long *fp_regs)
> {
> - struct iovec iov;
> -
> if (have_xstate_support) {
> +#ifdef PTRACE_SETREGSET
> + struct iovec iov;
> +
> iov.iov_base = fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
> return -errno;
> +#endif
> return 0;
> } else {
> return restore_i387_registers(pid, fp_regs);
> @@ -127,8 +130,10 @@ void arch_init_registers(int pid)
>
> iov.iov_base = &fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> +#ifdef PTRACE_GETREGSET
> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
> have_xstate_support = 1;
> +#endif
> }
> #endif
>
> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
> index cb3c22370cf5..8af0fb5d2780 100644
> --- a/arch/x86/um/user-offsets.c
> +++ b/arch/x86/um/user-offsets.c
> @@ -50,7 +50,11 @@ void foo(void)
> DEFINE(HOST_GS, GS);
> DEFINE(HOST_ORIG_AX, ORIG_EAX);
> #else
> +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
> DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
> +#else
> + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
> +#endif
> DEFINE_LONGS(HOST_BX, RBX);
> DEFINE_LONGS(HOST_CX, RCX);
> DEFINE_LONGS(HOST_DI, RDI);
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] um: Allow building and running on older hosts
2017-05-24 7:01 ` Richard Weinberger
@ 2017-05-24 9:03 ` Thomas Meyer
2017-05-24 16:27 ` Florian Fainelli
0 siblings, 1 reply; 4+ messages in thread
From: Thomas Meyer @ 2017-05-24 9:03 UTC (permalink / raw)
To: Richard Weinberger
Cc: Florian Fainelli, linux-kernel, elicooper, Jeff Dike,
Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
open list:USER-MODE LINUX (UML), open list:USER-MODE LINUX (UML)
[-- Attachment #1: Type: text/plain, Size: 3741 bytes --]
> Am 24.05.2017 um 09:01 schrieb Richard Weinberger <richard@nod.at>:
>
> CC'ing Thomas. We is also facing issues with these commits.
>
>> Am 24.05.2017 um 03:08 schrieb Florian Fainelli:
>> Commit a78ff1112263 ("um: add extended processor state save/restore
>> support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
>> YMM registers") forced the use of the x86 FP _xstate and
>> PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
>> build UML nor run it anymore with these two commits applied because we
>> don't have definitions for struct _xstate nor these two ptrace requests.
>>
>> We can determine at build time which fp context structure to check
>> against, just like we can keep using the old i387 fp save/restore if
>> PTRACE_GETRESET/SETREGSET are not defined.
>>
>> Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
>> Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>> ---
>> arch/x86/um/os-Linux/registers.c | 13 +++++++++----
>> arch/x86/um/user-offsets.c | 4 ++++
>> 2 files changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
>> index 00f54a91bb4b..502bd642e5c2 100644
>> --- a/arch/x86/um/os-Linux/registers.c
>> +++ b/arch/x86/um/os-Linux/registers.c
>> @@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
>>
>> int save_fp_registers(int pid, unsigned long *fp_regs)
>> {
>> - struct iovec iov;
>> -
>> if (have_xstate_support) {
>> +#ifdef PTRACE_GETREGSET
>> + struct iovec iov;
Is this okay, in C90? Won't this give an error once the thing is defined?
>> iov.iov_base = fp_regs;
>> iov.iov_len = sizeof(struct _xstate);
>> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
>> return -errno;
>> +#endif
>> return 0;
>> } else {
>> return save_i387_registers(pid, fp_regs);
>> @@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long *fp_regs)
>>
>> int restore_fp_registers(int pid, unsigned long *fp_regs)
>> {
>> - struct iovec iov;
>> -
>> if (have_xstate_support) {
>> +#ifdef PTRACE_SETREGSET
>> + struct iovec iov;
>> +
>> iov.iov_base = fp_regs;
>> iov.iov_len = sizeof(struct _xstate);
>> if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
>> return -errno;
>> +#endif
>> return 0;
>> } else {
>> return restore_i387_registers(pid, fp_regs);
>> @@ -127,8 +130,10 @@ void arch_init_registers(int pid)
>>
>> iov.iov_base = &fp_regs;
>> iov.iov_len = sizeof(struct _xstate);
>> +#ifdef PTRACE_GETREGSET
>> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
>> have_xstate_support = 1;
So why keep have_xstate_support when all branches that test for it are now pre compiler conditionals?
>> +#endif
>> }
>> #endif
>>
>> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
>> index cb3c22370cf5..8af0fb5d2780 100644
>> --- a/arch/x86/um/user-offsets.c
>> +++ b/arch/x86/um/user-offsets.c
>> @@ -50,7 +50,11 @@ void foo(void)
>> DEFINE(HOST_GS, GS);
>> DEFINE(HOST_ORIG_AX, ORIG_EAX);
>> #else
>> +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
>> DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
>> +#else
>> + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
>> +#endif
>> DEFINE_LONGS(HOST_BX, RBX);
>> DEFINE_LONGS(HOST_CX, RCX);
>> DEFINE_LONGS(HOST_DI, RDI);
>>
[-- Attachment #2: smime.p7s --]
[-- Type: application/pkcs7-signature, Size: 5334 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] um: Allow building and running on older hosts
2017-05-24 9:03 ` Thomas Meyer
@ 2017-05-24 16:27 ` Florian Fainelli
0 siblings, 0 replies; 4+ messages in thread
From: Florian Fainelli @ 2017-05-24 16:27 UTC (permalink / raw)
To: Thomas Meyer, Richard Weinberger
Cc: linux-kernel, elicooper, Jeff Dike, Thomas Gleixner, Ingo Molnar,
H. Peter Anvin, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
open list:USER-MODE LINUX (UML), open list:USER-MODE LINUX (UML)
On 05/24/2017 02:03 AM, Thomas Meyer wrote:
>
>> Am 24.05.2017 um 09:01 schrieb Richard Weinberger <richard@nod.at>:
>>
>> CC'ing Thomas. We is also facing issues with these commits.
>>
>>> Am 24.05.2017 um 03:08 schrieb Florian Fainelli:
>>> Commit a78ff1112263 ("um: add extended processor state save/restore
>>> support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
>>> YMM registers") forced the use of the x86 FP _xstate and
>>> PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
>>> build UML nor run it anymore with these two commits applied because we
>>> don't have definitions for struct _xstate nor these two ptrace requests.
>>>
>>> We can determine at build time which fp context structure to check
>>> against, just like we can keep using the old i387 fp save/restore if
>>> PTRACE_GETRESET/SETREGSET are not defined.
>>>
>>> Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
>>> Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>>> ---
>>> arch/x86/um/os-Linux/registers.c | 13 +++++++++----
>>> arch/x86/um/user-offsets.c | 4 ++++
>>> 2 files changed, 13 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
>>> index 00f54a91bb4b..502bd642e5c2 100644
>>> --- a/arch/x86/um/os-Linux/registers.c
>>> +++ b/arch/x86/um/os-Linux/registers.c
>>> @@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
>>>
>>> int save_fp_registers(int pid, unsigned long *fp_regs)
>>> {
>>> - struct iovec iov;
>>> -
>>> if (have_xstate_support) {
>>> +#ifdef PTRACE_GETREGSET
>>> + struct iovec iov;
>
> Is this okay, in C90? Won't this give an error once the thing is defined?
I did not get such a warning to be generated, but arguably I am using a
fairly hold host/compiler (GCC 4.4) let me try on something newer as well.
>
>>> iov.iov_base = fp_regs;
>>> iov.iov_len = sizeof(struct _xstate);
>>> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
>>> return -errno;
>>> +#endif
>>> return 0;
>>> } else {
>>> return save_i387_registers(pid, fp_regs);
>>> @@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long *fp_regs)
>>>
>>> int restore_fp_registers(int pid, unsigned long *fp_regs)
>>> {
>>> - struct iovec iov;
>>> -
>>> if (have_xstate_support) {
>>> +#ifdef PTRACE_SETREGSET
>>> + struct iovec iov;
>>> +
>>> iov.iov_base = fp_regs;
>>> iov.iov_len = sizeof(struct _xstate);
>>> if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
>>> return -errno;
>>> +#endif
>>> return 0;
>>> } else {
>>> return restore_i387_registers(pid, fp_regs);
>>> @@ -127,8 +130,10 @@ void arch_init_registers(int pid)
>>>
>>> iov.iov_base = &fp_regs;
>>> iov.iov_len = sizeof(struct _xstate);
>>> +#ifdef PTRACE_GETREGSET
>>> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
>>> have_xstate_support = 1;
>
> So why keep have_xstate_support when all branches that test for it are now pre compiler conditionals?
To minimize the amount of lines needed to account for lack of
PTRACE_SETREGSET/GETREGSET, and to keep the if(0) else() semi-explicit here.
Would you prefer that instead:
diff --git a/arch/x86/um/os-Linux/registers.c
b/arch/x86/um/os-Linux/registers.c
index 00f54a91bb4b..b342bbfbb8d2 100644
--- a/arch/x86/um/os-Linux/registers.c
+++ b/arch/x86/um/os-Linux/registers.c
@@ -26,6 +26,7 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
int save_fp_registers(int pid, unsigned long *fp_regs)
{
+#ifdef PTRACE_GETREGSET
struct iovec iov;
if (have_xstate_support) {
@@ -34,9 +35,9 @@ int save_fp_registers(int pid, unsigned long *fp_regs)
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
- } else {
+ } else
+#endif
return save_i387_registers(pid, fp_regs);
- }
}
int restore_i387_registers(int pid, unsigned long *fp_regs)
@@ -48,6 +49,7 @@ int restore_i387_registers(int pid, unsigned long
*fp_regs)
int restore_fp_registers(int pid, unsigned long *fp_regs)
{
+#ifdef PTRACE_SETREGSET
struct iovec iov;
if (have_xstate_support) {
@@ -56,9 +58,9 @@ int restore_fp_registers(int pid, unsigned long *fp_regs)
if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
- } else {
+ } else
+#endif
return restore_i387_registers(pid, fp_regs);
- }
}
#ifdef __i386__
>
>>> +#endif
>>> }
>>> #endif
>>>
>>> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
>>> index cb3c22370cf5..8af0fb5d2780 100644
>>> --- a/arch/x86/um/user-offsets.c
>>> +++ b/arch/x86/um/user-offsets.c
>>> @@ -50,7 +50,11 @@ void foo(void)
>>> DEFINE(HOST_GS, GS);
>>> DEFINE(HOST_ORIG_AX, ORIG_EAX);
>>> #else
>>> +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
>>> DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
>>> +#else
>>> + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
>>> +#endif
>>> DEFINE_LONGS(HOST_BX, RBX);
>>> DEFINE_LONGS(HOST_CX, RCX);
>>> DEFINE_LONGS(HOST_DI, RDI);
>>>
--
Florian
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-05-24 16:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-05-24 1:08 [PATCH] um: Allow building and running on older hosts Florian Fainelli
2017-05-24 7:01 ` Richard Weinberger
2017-05-24 9:03 ` Thomas Meyer
2017-05-24 16:27 ` Florian Fainelli
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox