Hi Mykola,
Mykola Kvach <xakep.ama...@gmail.com> writes:
> From: Mirela Simonovic <mirela.simono...@aggios.com>
>
> System suspend may lead to a state where GIC would be powered down.
> Therefore, Xen should save/restore the context of GIC on suspend/resume.
>
> Note that the context consists of states of registers which are
> controlled by the hypervisor. Other GIC registers which are accessible
> by guests are saved/restored on context switch.
>
> Tested on Xilinx Ultrascale+ MPSoC with (and without) powering down
> the GIC.
I think you can drop this sentence, as I am pretty sure this patch
wasn't tested on Ultrascale+ for last five(?) years..
>
> Signed-off-by: Mirela Simonovic <mirela.simono...@aggios.com>
> Signed-off-by: Saeed Nowshadi <saeed.nowsh...@xilinx.com>
> Signed-off-by: Mykyta Poturai <mykyta_potu...@epam.com>
> Signed-off-by: Mykola Kvach <mykola_kv...@epam.com>
> ---
> Changes in v4:
> - Add error logging for allocation failures
>
> Changes in v3:
> - Drop asserts and return error codes instead.
> - Wrap code with CONFIG_SYSTEM_SUSPEND.
>
> Changes in v2:
> - Minor fixes after review.
> ---
> xen/arch/arm/gic-v2.c | 154 +++++++++++++++++++++++++++++++++
> xen/arch/arm/gic.c | 29 +++++++
> xen/arch/arm/include/asm/gic.h | 12 +++
> 3 files changed, 195 insertions(+)
>
> diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
> index b23e72a3d0..dce8f5e924 100644
> --- a/xen/arch/arm/gic-v2.c
> +++ b/xen/arch/arm/gic-v2.c
> @@ -1098,6 +1098,151 @@ static int gicv2_iomem_deny_access(struct domain *d)
> return iomem_deny_access(d, mfn, mfn + nr);
> }
>
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +
> +/* GICv2 registers to be saved/restored on system suspend/resume */
> +struct gicv2_context {
> + /* GICC context */
> + uint32_t gicc_ctlr;
> + uint32_t gicc_pmr;
> + uint32_t gicc_bpr;
> + /* GICD context */
> + uint32_t gicd_ctlr;
> + uint32_t *gicd_isenabler;
> + uint32_t *gicd_isactiver;
> + uint32_t *gicd_ipriorityr;
> + uint32_t *gicd_itargetsr;
> + uint32_t *gicd_icfgr;
> +};
> +
> +static struct gicv2_context gicv2_context;
> +
> +static int gicv2_suspend(void)
> +{
> + unsigned int i;
> +
> + if ( !gicv2_context.gicd_isenabler )
> + {
> + dprintk(XENLOG_WARNING, "%s:%d: GICv2 suspend context not
> allocated!\n",
> + __func__, __LINE__);
Should this be ASSERT(gicv2_context.gicd_isenabler) ? Or do we expect
that this can happen during normal runtime?
Also, you don't need to print __func__ and __LINE__ as dprintk does this
for you already:
#define dprintk(lvl, fmt, args...) \
printk(lvl "%s:%d: " fmt, __FILE__, __LINE__, ## args)
> + return -ENOMEM;
> + }
> +
> + /* Save GICC configuration */
> + gicv2_context.gicc_ctlr = readl_gicc(GICC_CTLR);
> + gicv2_context.gicc_pmr = readl_gicc(GICC_PMR);
> + gicv2_context.gicc_bpr = readl_gicc(GICC_BPR);
> +
> + /* Save GICD configuration */
> + gicv2_context.gicd_ctlr = readl_gicd(GICD_CTLR);
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 32); i++ )
> + gicv2_context.gicd_isenabler[i] = readl_gicd(GICD_ISENABLER + i * 4);
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 32); i++ )
> + gicv2_context.gicd_isactiver[i] = readl_gicd(GICD_ISACTIVER + i * 4);
> +
I think you can merge this two loops
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 4); i++ )
> + gicv2_context.gicd_ipriorityr[i] = readl_gicd(GICD_IPRIORITYR + i *
> 4);
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 4); i++ )
> + gicv2_context.gicd_itargetsr[i] = readl_gicd(GICD_ITARGETSR + i * 4);
> +
And this two as well
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 16); i++ )
> + gicv2_context.gicd_icfgr[i] = readl_gicd(GICD_ICFGR + i * 4);
> +
> + return 0;
> +}
> +
> +static void gicv2_resume(void)
> +{
> + unsigned int i;
> +
> + if ( !gicv2_context.gicd_isenabler )
> + {
> + dprintk(XENLOG_WARNING, "%s:%d: GICv2 suspend context not
> allocated!\n",
> + __func__, __LINE__);
the same comment as for gicv2_suspend(). Actually, we should not reach
here in any case.
> + return;
> + }
> +
> + gicv2_cpu_disable();
> + /* Disable distributor */
> + writel_gicd(0, GICD_CTLR);
> +
> + /* Restore GICD configuration */
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 32); i++ ) {
> + writel_gicd(0xffffffff, GICD_ICENABLER + i * 4);
> + writel_gicd(gicv2_context.gicd_isenabler[i], GICD_ISENABLER + i * 4);
> + }
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 32); i++ ) {
> + writel_gicd(0xffffffff, GICD_ICACTIVER + i * 4);
> + writel_gicd(gicv2_context.gicd_isactiver[i], GICD_ISACTIVER + i * 4);
> + }
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 4); i++ )
> + writel_gicd(gicv2_context.gicd_ipriorityr[i], GICD_IPRIORITYR + i *
> 4);
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 4); i++ )
> + writel_gicd(gicv2_context.gicd_itargetsr[i], GICD_ITARGETSR + i * 4);
> +
> + for ( i = 0; i < DIV_ROUND_UP(gicv2_info.nr_lines, 16); i++ )
> + writel_gicd(gicv2_context.gicd_icfgr[i], GICD_ICFGR + i * 4);
> +
> + /* Make sure all registers are restored and enable distributor */
> + writel_gicd(gicv2_context.gicd_ctlr | GICD_CTL_ENABLE, GICD_CTLR);
> +
> + /* Restore GIC CPU interface configuration */
> + writel_gicc(gicv2_context.gicc_pmr, GICC_PMR);
> + writel_gicc(gicv2_context.gicc_bpr, GICC_BPR);
> +
> + /* Enable GIC CPU interface */
> + writel_gicc(gicv2_context.gicc_ctlr | GICC_CTL_ENABLE | GICC_CTL_EOI,
> + GICC_CTLR);
> +}
> +
> +static void gicv2_alloc_context(struct gicv2_context *gc)
> +{
> + uint32_t n = gicv2_info.nr_lines;
> +
> + gc->gicd_isenabler = xzalloc_array(uint32_t, DIV_ROUND_UP(n, 32));
> + if ( !gc->gicd_isenabler )
> + goto err_free;
> +
> + gc->gicd_isactiver = xzalloc_array(uint32_t, DIV_ROUND_UP(n, 32));
> + if ( !gc->gicd_isactiver )
> + goto err_free;
> +
> + gc->gicd_itargetsr = xzalloc_array(uint32_t, DIV_ROUND_UP(n, 4));
> + if ( !gc->gicd_itargetsr )
> + goto err_free;
> +
> + gc->gicd_ipriorityr = xzalloc_array(uint32_t, DIV_ROUND_UP(n, 4));
> + if ( !gc->gicd_ipriorityr )
> + goto err_free;
> +
> + gc->gicd_icfgr = xzalloc_array(uint32_t, DIV_ROUND_UP(n, 16));
> + if ( !gc->gicd_icfgr )
> + goto err_free;
> +
> + return;
> +
> + err_free:
> + dprintk(XENLOG_ERR,
> + "%s:%d: failed to allocate memory for GICv2 suspend context\n",
> + __func__, __LINE__);
Okay, this partially answers to my previous question about memory
allocation. So it is possible to have active system without space for
GIC context... But this basically renders system un-suspendable. I think
this warrants non-debug print to warn user that suspend will be not
available.
[...]
--
WBR, Volodymyr
