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* [PATCH] riscv: add S and U modes to ISA string
@ 2018-11-10  6:45 david.abdurachmanov
  2018-11-10  6:45 ` David Abdurachmanov
  2018-11-10  8:35 ` me
  0 siblings, 2 replies; 8+ messages in thread
From: david.abdurachmanov @ 2018-11-10  6:45 UTC (permalink / raw)
  To: linux-riscv

Booting kernel (4.20-rc1) with riscv-pk @
6ebd0f2a46255d0c76dad3c05b16c1d154795d26 (master/HEAD) on Fedora 29 one gets:

[..]
[   55.075000] unsupported ISA "rv64imafdcsu" in device tree
[   55.075000] unsupported ISA "rv64imafdcsu" in device tree
[   55.076000] unsupported ISA "rv64imafdcsu" in device tree
[   55.076000] unsupported ISA "rv64imafdcsu" in device tree
[   55.077000] systemd[1]: Detected architecture riscv64.
[..]

The patch adds the missing S and U modes.

Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
---
 arch/riscv/kernel/cpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 3a5a2ee31547..4029c7e6872b 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -64,7 +64,7 @@ int riscv_of_processor_hartid(struct device_node *node)
 
 static void print_isa(struct seq_file *f, const char *orig_isa)
 {
-	static const char *ext = "mafdc";
+	static const char *ext = "mafdcsu";
 	const char *isa = orig_isa;
 	const char *e;
 
-- 
2.19.1

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH] riscv: add S and U modes to ISA string
  2018-11-10  6:45 [PATCH] riscv: add S and U modes to ISA string david.abdurachmanov
@ 2018-11-10  6:45 ` David Abdurachmanov
  2018-11-10  8:35 ` me
  1 sibling, 0 replies; 8+ messages in thread
From: David Abdurachmanov @ 2018-11-10  6:45 UTC (permalink / raw)
  To: palmer, aou, linux-riscv, linux-kernel; +Cc: David Abdurachmanov

Booting kernel (4.20-rc1) with riscv-pk @
6ebd0f2a46255d0c76dad3c05b16c1d154795d26 (master/HEAD) on Fedora 29 one gets:

[..]
[   55.075000] unsupported ISA "rv64imafdcsu" in device tree
[   55.075000] unsupported ISA "rv64imafdcsu" in device tree
[   55.076000] unsupported ISA "rv64imafdcsu" in device tree
[   55.076000] unsupported ISA "rv64imafdcsu" in device tree
[   55.077000] systemd[1]: Detected architecture riscv64.
[..]

The patch adds the missing S and U modes.

Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
---
 arch/riscv/kernel/cpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 3a5a2ee31547..4029c7e6872b 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -64,7 +64,7 @@ int riscv_of_processor_hartid(struct device_node *node)
 
 static void print_isa(struct seq_file *f, const char *orig_isa)
 {
-	static const char *ext = "mafdc";
+	static const char *ext = "mafdcsu";
 	const char *isa = orig_isa;
 	const char *e;
 
-- 
2.19.1


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http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH] riscv: add S and U modes to ISA string
  2018-11-10  6:45 [PATCH] riscv: add S and U modes to ISA string david.abdurachmanov
  2018-11-10  6:45 ` David Abdurachmanov
@ 2018-11-10  8:35 ` me
  2018-11-10  8:35   ` Patrick Staehlin
  2018-11-11 22:14   ` palmer
  1 sibling, 2 replies; 8+ messages in thread
From: me @ 2018-11-10  8:35 UTC (permalink / raw)
  To: linux-riscv

On 10.11.18 07:45, David Abdurachmanov wrote:
> 
> The patch adds the missing S and U modes.

This is the same patch I submitted earlier (see v2 here [1], based on
Palmer's feedback). Palmer stated that the "S" extension should not be
exposed to usermode.

Since two people arrived at the same solution, I wonder if the
supervisor mode should really be hidden from userspace, as it's about
the CPU information, not about the environment the calling code is
running as.

[1] https://lkml.org/lkml/2018/11/10/96

Patrick

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] riscv: add S and U modes to ISA string
  2018-11-10  8:35 ` me
@ 2018-11-10  8:35   ` Patrick Staehlin
  2018-11-11 22:14   ` palmer
  1 sibling, 0 replies; 8+ messages in thread
From: Patrick Staehlin @ 2018-11-10  8:35 UTC (permalink / raw)
  To: David Abdurachmanov, palmer, aou, linux-riscv, linux-kernel

On 10.11.18 07:45, David Abdurachmanov wrote:
> 
> The patch adds the missing S and U modes.

This is the same patch I submitted earlier (see v2 here [1], based on
Palmer's feedback). Palmer stated that the "S" extension should not be
exposed to usermode.

Since two people arrived at the same solution, I wonder if the
supervisor mode should really be hidden from userspace, as it's about
the CPU information, not about the environment the calling code is
running as.

[1] https://lkml.org/lkml/2018/11/10/96

Patrick

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH] riscv: add S and U modes to ISA string
  2018-11-10  8:35 ` me
  2018-11-10  8:35   ` Patrick Staehlin
@ 2018-11-11 22:14   ` palmer
  2018-11-11 22:14     ` Palmer Dabbelt
  2018-11-12  6:29     ` david.abdurachmanov
  1 sibling, 2 replies; 8+ messages in thread
From: palmer @ 2018-11-11 22:14 UTC (permalink / raw)
  To: linux-riscv

On Sat, 10 Nov 2018 00:35:15 PST (-0800), me at packi.ch wrote:
> On 10.11.18 07:45, David Abdurachmanov wrote:
>>
>> The patch adds the missing S and U modes.
>
> This is the same patch I submitted earlier (see v2 here [1], based on
> Palmer's feedback). Palmer stated that the "S" extension should not be
> exposed to usermode.
>
> Since two people arrived at the same solution, I wonder if the
> supervisor mode should really be hidden from userspace, as it's about
> the CPU information, not about the environment the calling code is
> running as.
>
> [1] https://lkml.org/lkml/2018/11/10/96

I still think S should be hidden from applications.  This patch was fairly 
mechanical, so it probably just wasn't though about twice -- that's the problem 
with user ABI stuff, lots of times the obvious answer isn't the correct one :).

I'll take your second patch, I just haven't gotten around to actually fully 
reviewing patches yet as I'm still in my email triage phase.

Thanks!

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] riscv: add S and U modes to ISA string
  2018-11-11 22:14   ` palmer
@ 2018-11-11 22:14     ` Palmer Dabbelt
  2018-11-12  6:29     ` david.abdurachmanov
  1 sibling, 0 replies; 8+ messages in thread
From: Palmer Dabbelt @ 2018-11-11 22:14 UTC (permalink / raw)
  To: me; +Cc: linux-riscv, aou, linux-kernel, david.abdurachmanov

On Sat, 10 Nov 2018 00:35:15 PST (-0800), me@packi.ch wrote:
> On 10.11.18 07:45, David Abdurachmanov wrote:
>>
>> The patch adds the missing S and U modes.
>
> This is the same patch I submitted earlier (see v2 here [1], based on
> Palmer's feedback). Palmer stated that the "S" extension should not be
> exposed to usermode.
>
> Since two people arrived at the same solution, I wonder if the
> supervisor mode should really be hidden from userspace, as it's about
> the CPU information, not about the environment the calling code is
> running as.
>
> [1] https://lkml.org/lkml/2018/11/10/96

I still think S should be hidden from applications.  This patch was fairly 
mechanical, so it probably just wasn't though about twice -- that's the problem 
with user ABI stuff, lots of times the obvious answer isn't the correct one :).

I'll take your second patch, I just haven't gotten around to actually fully 
reviewing patches yet as I'm still in my email triage phase.

Thanks!

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH] riscv: add S and U modes to ISA string
  2018-11-11 22:14   ` palmer
  2018-11-11 22:14     ` Palmer Dabbelt
@ 2018-11-12  6:29     ` david.abdurachmanov
  2018-11-12  6:29       ` David Abdurachmanov
  1 sibling, 1 reply; 8+ messages in thread
From: david.abdurachmanov @ 2018-11-12  6:29 UTC (permalink / raw)
  To: linux-riscv

On Sun, Nov 11, 2018 at 11:14 PM Palmer Dabbelt <palmer@sifive.com> wrote:
>
> On Sat, 10 Nov 2018 00:35:15 PST (-0800), me at packi.ch wrote:
> > On 10.11.18 07:45, David Abdurachmanov wrote:
> >>
> >> The patch adds the missing S and U modes.
> >
> > This is the same patch I submitted earlier (see v2 here [1], based on
> > Palmer's feedback). Palmer stated that the "S" extension should not be
> > exposed to usermode.
> >
> > Since two people arrived at the same solution, I wonder if the
> > supervisor mode should really be hidden from userspace, as it's about
> > the CPU information, not about the environment the calling code is
> > running as.
> >
> > [1] https://lkml.org/lkml/2018/11/10/96
>
> I still think S should be hidden from applications.  This patch was fairly
> mechanical, so it probably just wasn't though about twice -- that's the problem
> with user ABI stuff, lots of times the obvious answer isn't the correct one :).
>
True. It was mechanical based on warnings I noticed while booting Fedora
with latest kernel and BBL.

Also true, that /proc/cpuinfo doesn't need to reveal all things to user space
(especially if you don't want various programs to depend on it as some
tend to parse /proc/cpuinfo).

Note, that on server systems which probably would implement SMBIOS
(based on the current proposal for RISC-V) the administrator could
check for S mode.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] riscv: add S and U modes to ISA string
  2018-11-12  6:29     ` david.abdurachmanov
@ 2018-11-12  6:29       ` David Abdurachmanov
  0 siblings, 0 replies; 8+ messages in thread
From: David Abdurachmanov @ 2018-11-12  6:29 UTC (permalink / raw)
  To: Palmer Dabbelt; +Cc: me, aou, linux-riscv, linux-kernel

On Sun, Nov 11, 2018 at 11:14 PM Palmer Dabbelt <palmer@sifive.com> wrote:
>
> On Sat, 10 Nov 2018 00:35:15 PST (-0800), me@packi.ch wrote:
> > On 10.11.18 07:45, David Abdurachmanov wrote:
> >>
> >> The patch adds the missing S and U modes.
> >
> > This is the same patch I submitted earlier (see v2 here [1], based on
> > Palmer's feedback). Palmer stated that the "S" extension should not be
> > exposed to usermode.
> >
> > Since two people arrived at the same solution, I wonder if the
> > supervisor mode should really be hidden from userspace, as it's about
> > the CPU information, not about the environment the calling code is
> > running as.
> >
> > [1] https://lkml.org/lkml/2018/11/10/96
>
> I still think S should be hidden from applications.  This patch was fairly
> mechanical, so it probably just wasn't though about twice -- that's the problem
> with user ABI stuff, lots of times the obvious answer isn't the correct one :).
>
True. It was mechanical based on warnings I noticed while booting Fedora
with latest kernel and BBL.

Also true, that /proc/cpuinfo doesn't need to reveal all things to user space
(especially if you don't want various programs to depend on it as some
tend to parse /proc/cpuinfo).

Note, that on server systems which probably would implement SMBIOS
(based on the current proposal for RISC-V) the administrator could
check for S mode.

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 8+ messages in thread

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Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-10  6:45 [PATCH] riscv: add S and U modes to ISA string david.abdurachmanov
2018-11-10  6:45 ` David Abdurachmanov
2018-11-10  8:35 ` me
2018-11-10  8:35   ` Patrick Staehlin
2018-11-11 22:14   ` palmer
2018-11-11 22:14     ` Palmer Dabbelt
2018-11-12  6:29     ` david.abdurachmanov
2018-11-12  6:29       ` David Abdurachmanov

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