On 11 November 2013 09:47, Vijay Kilari vijay.kilari@gmail.com wrote:
On Fri, Nov 8, 2013 at 8:36 PM, Will Deacon will.deacon@arm.com wrote:
On Thu, Nov 07, 2013 at 12:38:41PM +0000, vijay.kilari@gmail.com wrote:
From: Vijaya Kumar K Vijaya.Kumar@caviumnetworks.com
Add KGDB debug support for FP/SIMD processor.This support only debugging of FP/SIMD in kernel mode. With this patch one can view or set FP/SIMD registers in kernel context
Signed-off-by: Vijaya Kumar K Vijaya.Kumar@caviumnetworks.com
arch/arm64/kernel/kgdb.c | 98 ++++++++++++++++++++++++++++------------------ 1 file changed, 60 insertions(+), 38 deletions(-)
[...]
@@ -100,11 +108,18 @@ char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) if (regno >= DBG_MAX_REG_NUM || regno < 0) return NULL;
if (dbg_reg_def[regno].offset != -1)
if (dbg_reg_def[regno].offset != -1 && regno < _GP_REGS) memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, dbg_reg_def[regno].size);
else
else {+#ifdef CONFIG_KERNEL_MODE_NEON
fpsimd_save_state(&kgdb_fpsimd_regs);memcpy(mem, (void *)&kgdb_fpsimd_regs +dbg_reg_def[regno].offset, dbg_reg_def[regno].size);Don't you only want to do this if you're inside a kernel_neon_{begin,end} section? Otherwise, you'll be copying out user registers. It really depends on what semantics you want.
Yes, we can do that. I couldn't find any api to know the state of the neon. I think of using a status variable and update in kernel_neon_begin/end?
I have posted a patch here
http://marc.info/?l=linux-arm-kernel&m=138324498203157&w=2
that already keeps track of whether the current NEON register contents belong to the current userland or not. This is for a different purpose (lazy restore) but could potentially be reused here I suppose.