From: David Daney <ddaney.cavm@gmail.com>
To: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Subject: Re: [PATCH 15/15] mips: save/restore MSA context around signals
Date: Mon, 27 Jan 2014 11:50:31 -0800 [thread overview]
Message-ID: <52E6B887.2070605@gmail.com> (raw)
In-Reply-To: <1390836194-26286-16-git-send-email-paul.burton@imgtec.com>
On 01/27/2014 07:23 AM, Paul Burton wrote:
> This patch extends sigcontext in order to hold the most significant 64
> bits of each vector register in addition to the MSA control & status
> register. The least significant 64 bits are already saved as the scalar
> FP context. This makes things a little awkward since the least & most
> significant 64 bits of each vector register are not contiguous in
> memory. Thus the copy_u & insert instructions are used to transfer the
> values of the most significant 64 bits via GP registers.
>
Interesting.
This very much touches the userspace ABI of the kernel, so it merits
very careful consideration.
> Signed-off-by: Paul Burton <paul.burton@imgtec.com>
> ---
> arch/mips/include/asm/sigcontext.h | 2 +
> arch/mips/include/uapi/asm/sigcontext.h | 8 ++
> arch/mips/kernel/asm-offsets.c | 3 +
> arch/mips/kernel/r4k_fpu.S | 213 ++++++++++++++++++++++++++++++++
> arch/mips/kernel/signal.c | 71 +++++++++--
> arch/mips/kernel/signal32.c | 71 +++++++++--
> 6 files changed, 352 insertions(+), 16 deletions(-)
>
[...]
> diff --git a/arch/mips/include/uapi/asm/sigcontext.h b/arch/mips/include/uapi/asm/sigcontext.h
> index 6c9906f..681c176 100644
> --- a/arch/mips/include/uapi/asm/sigcontext.h
> +++ b/arch/mips/include/uapi/asm/sigcontext.h
> @@ -12,6 +12,10 @@
> #include <linux/types.h>
> #include <asm/sgidefs.h>
>
> +/* Bits which may be set in sc_used_math */
> +#define USEDMATH_FP (1 << 0)
> +#define USEDMATH_MSA (1 << 1)
> +
How is this going to interact with existing userspace applications?
Is the current behavior to use / manipulate sc_used_math?
How will USEDMATH_MSA interact with existing code?
next prev parent reply other threads:[~2014-01-27 19:50 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 15:22 [PATCH 00/15] Initial MSA support Paul Burton
2014-01-27 15:22 ` Paul Burton
2014-01-27 15:23 ` [PATCH v2 01/15] mips: simplify FP context access Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-02-13 11:26 ` [PATCH v3 " Paul Burton
2014-02-13 11:26 ` Paul Burton
2014-01-27 15:23 ` [PATCH 02/15] mips: update outdated comment Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 03/15] mips: move & rename fpu_emulator_{save,restore}_context Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 04/15] mips: don't require FPU on sigcontext setup/restore Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 05/15] mips: replace hardcoded 32 with NUM_FPU_REGS in ptrace Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 06/15] mips: clear upper bits of FP registers on emulator writes Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 18:06 ` Sergei Shtylyov
2014-01-27 17:11 ` Paul Burton
2014-01-27 17:11 ` Paul Burton
2014-01-27 17:14 ` [PATCH v2 " Paul Burton
2014-01-27 17:14 ` Paul Burton
2014-01-27 15:23 ` [PATCH 07/15] mips: don't assume 64-bit FP registers for dump_{,task_}fpu Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 08/15] mips: don't assume 64-bit FP registers for FP regset Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 09/15] mips: don't assume 64-bit FP registers for context switch Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 10/15] mips: add MSA register definitions & access Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 11/15] mips: detect the MSA ASE Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 12/15] mips: basic MSA context switching support Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 13/15] mips: dumb MSA FP exception handler Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 15:23 ` [PATCH 14/15] mips: panic if vector register partitioning is implemented Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 18:38 ` David Daney
2014-01-27 19:39 ` Paul Burton
2014-01-27 19:39 ` Paul Burton
2014-01-27 19:56 ` David Daney
2014-01-28 14:20 ` Paul Burton
2014-01-28 14:20 ` Paul Burton
2014-01-28 14:28 ` [PATCH v2 14/15] mips: warn " Paul Burton
2014-01-28 14:28 ` Paul Burton
2014-01-27 15:23 ` [PATCH 15/15] mips: save/restore MSA context around signals Paul Burton
2014-01-27 15:23 ` Paul Burton
2014-01-27 19:50 ` David Daney [this message]
2014-01-27 20:06 ` Paul Burton
2014-01-27 20:06 ` Paul Burton
2014-02-13 11:27 ` [PATCH v2 " Paul Burton
2014-02-13 11:27 ` Paul Burton
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