[PATCHv3] ARM: omap2+: Revert omap-smp.c changes resetting CPU1 during boot
Tony Lindgren
tony at atomide.com
Tue Mar 14 11:05:55 PDT 2017
Commit 3251885285e1 ("ARM: OMAP4+: Reset CPU1 properly for kexec") started
unconditionally resetting CPU1 because of a kexec boot issue I was seeing
earlier on omap4 when doing kexec boot between two different kernel
versions.
This caused issues on some systems. We should only reset CPU1 as a last
resort option, and try to avoid it where possible. Doing an unconditional
CPU1 reset causes issues for example when booting a bootloader configured
secure OS running on CPU1 as reported by Andrew F. Davis <afd at ti.com>.
We can't completely remove the reset of CPU1 as it would break kexec
booting from older kernels. But we can limit the CPU1 reset to cases
where CPU1 is wrongly parked within the memory area used by the booting
kernel. Then later on we can add support for parking CPU1 for kexec out
of the SDRAM back to bootrom.
So let's first fix the regression reported by Andrew by making CPU1 reset
conditional. To do this, we need to:
1. Save configured AUX_CORE_BOOT_1 for later
2. Modify AUX_CORE_BOOT_0 reading code to for HS SoCs to return
the whole register instead of the CPU mask
3. Check if CPU1 is wrongly parked into the booting kernel by the
previous kernel and reset if needed
Fixes: 3251885285e1 ("ARM: OMAP4+: Reset CPU1 properly for kexec")
Reported-by: Andrew F. Davis <afd at ti.com>
Cc: Andrew F. Davis <afd at ti.com>
Cc: Keerthy <j-keerthy at ti.com>
Cc: Russell King <rmk+kernel at armlinux.org.uk>
Cc: Santosh Shilimkar <ssantosh at kernel.org>
Cc: Tero Kristo <t-kristo at ti.com>
Signed-off-by: Tony Lindgren <tony at atomide.com>
---
Changes from v2:
- Add Santosh to Cc, sorry Santosh I forgot to add earlier
- Add check for CPU1 being parked in addition to checking
CPU1 start-up address being within booting kernel before
reset
- Left out extra cpu_is to soc_is changes, those can be done
later
- Updated description to leave out suspend/resume issues as
those can be dealt with separately if they still exist after
fixing kexec boot, they may have been happening only after
a kexec boot
Changes from v1:
- We can't remove the CPU1 reset completely because it breaks
kexec booting all the existing kernels as CPU1 might be
parked into the booting kernel
---
arch/arm/mach-omap2/common.h | 1 +
arch/arm/mach-omap2/omap-hotplug.c | 2 +-
arch/arm/mach-omap2/omap-mpuss-lowpower.c | 22 ++++++--
arch/arm/mach-omap2/omap-smc.S | 1 -
arch/arm/mach-omap2/omap-smp.c | 90 ++++++++++++++++++++++++++-----
5 files changed, 96 insertions(+), 20 deletions(-)
diff --git a/arch/arm/mach-omap2/common.h b/arch/arm/mach-omap2/common.h
--- a/arch/arm/mach-omap2/common.h
+++ b/arch/arm/mach-omap2/common.h
@@ -270,6 +270,7 @@ extern const struct smp_operations omap4_smp_ops;
extern int omap4_mpuss_init(void);
extern int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state);
extern int omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state);
+extern u32 omap4_get_cpu1_ns_pa_addr(void);
#else
static inline int omap4_enter_lowpower(unsigned int cpu,
unsigned int power_state)
diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c
--- a/arch/arm/mach-omap2/omap-hotplug.c
+++ b/arch/arm/mach-omap2/omap-hotplug.c
@@ -50,7 +50,7 @@ void omap4_cpu_die(unsigned int cpu)
omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
if (omap_secure_apis_support())
- boot_cpu = omap_read_auxcoreboot0();
+ boot_cpu = omap_read_auxcoreboot0() >> 9;
else
boot_cpu =
readl_relaxed(base + OMAP_AUX_CORE_BOOT_0) >> 5;
diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -64,6 +64,7 @@
#include "prm-regbits-44xx.h"
static void __iomem *sar_base;
+static u32 old_cpu1_ns_pa_addr;
#if defined(CONFIG_PM) && defined(CONFIG_SMP)
@@ -212,6 +213,11 @@ static void __init save_l2x0_context(void)
{}
#endif
+u32 omap4_get_cpu1_ns_pa_addr(void)
+{
+ return old_cpu1_ns_pa_addr;
+}
+
/**
* omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
* The purpose of this function is to manage low power programming
@@ -460,22 +466,30 @@ int __init omap4_mpuss_init(void)
void __init omap4_mpuss_early_init(void)
{
unsigned long startup_pa;
+ void __iomem *ns_pa_addr;
- if (!(cpu_is_omap44xx() || soc_is_omap54xx()))
+ if (!(soc_is_omap44xx() || soc_is_omap54xx()))
return;
sar_base = omap4_get_sar_ram_base();
- if (cpu_is_omap443x())
+ /* Save old NS_PA_ADDR for validity checks later on */
+ if (soc_is_omap44xx())
+ ns_pa_addr = sar_base + CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
+ else
+ ns_pa_addr = sar_base + OMAP5_CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
+ old_cpu1_ns_pa_addr = readl_relaxed(ns_pa_addr);
+
+ if (soc_is_omap443x())
startup_pa = __pa_symbol(omap4_secondary_startup);
- else if (cpu_is_omap446x())
+ else if (soc_is_omap446x())
startup_pa = __pa_symbol(omap4460_secondary_startup);
else if ((__boot_cpu_mode & MODE_MASK) == HYP_MODE)
startup_pa = __pa_symbol(omap5_secondary_hyp_startup);
else
startup_pa = __pa_symbol(omap5_secondary_startup);
- if (cpu_is_omap44xx())
+ if (soc_is_omap44xx())
writel_relaxed(startup_pa, sar_base +
CPU1_WAKEUP_NS_PA_ADDR_OFFSET);
else
diff --git a/arch/arm/mach-omap2/omap-smc.S b/arch/arm/mach-omap2/omap-smc.S
--- a/arch/arm/mach-omap2/omap-smc.S
+++ b/arch/arm/mach-omap2/omap-smc.S
@@ -94,6 +94,5 @@ ENTRY(omap_read_auxcoreboot0)
ldr r12, =0x103
dsb
smc #0
- mov r0, r0, lsr #9
ldmfd sp!, {r2-r12, pc}
ENDPROC(omap_read_auxcoreboot0)
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -21,6 +21,7 @@
#include <linux/io.h>
#include <linux/irqchip/arm-gic.h>
+#include <asm/sections.h>
#include <asm/smp_scu.h>
#include <asm/virt.h>
@@ -40,10 +41,14 @@
#define OMAP5_CORE_COUNT 0x2
+#define AUX_CORE_BOOT0_GP_RELEASE 0x020
+#define AUX_CORE_BOOT0_HS_RELEASE 0x200
+
struct omap_smp_config {
unsigned long cpu1_rstctrl_pa;
void __iomem *cpu1_rstctrl_va;
void __iomem *scu_base;
+ void __iomem *wakeupgen_base;
void *startup_addr;
};
@@ -140,7 +145,6 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
static struct clockdomain *cpu1_clkdm;
static bool booted;
static struct powerdomain *cpu1_pwrdm;
- void __iomem *base = omap_get_wakeupgen_base();
/*
* Set synchronisation state between this boot processor
@@ -155,9 +159,11 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
* A barrier is added to ensure that write buffer is drained
*/
if (omap_secure_apis_support())
- omap_modify_auxcoreboot0(0x200, 0xfffffdff);
+ omap_modify_auxcoreboot0(AUX_CORE_BOOT0_HS_RELEASE,
+ 0xfffffdff);
else
- writel_relaxed(0x20, base + OMAP_AUX_CORE_BOOT_0);
+ writel_relaxed(AUX_CORE_BOOT0_GP_RELEASE,
+ cfg.wakeupgen_base + OMAP_AUX_CORE_BOOT_0);
if (!cpu1_clkdm && !cpu1_pwrdm) {
cpu1_clkdm = clkdm_lookup("mpu1_clkdm");
@@ -261,9 +267,72 @@ static void __init omap4_smp_init_cpus(void)
set_cpu_possible(i, true);
}
+/*
+ * For now, just make sure the start-up address is not within the booting
+ * kernel space as that means we just overwrote whatever secondary_startup()
+ * code there was.
+ */
+static bool __init omap4_smp_cpu1_startup_valid(unsigned long addr)
+{
+ if ((addr >= __pa(PAGE_OFFSET)) && (addr <= __pa(__bss_start)))
+ return false;
+
+ return true;
+}
+
+/*
+ * We may need to reset CPU1 before configuring, otherwise kexec boot can end
+ * up trying to use old kernel startup address or suspend-resume will
+ * occasionally fail to bring up CPU1 on 4430 if CPU1 fails to enter deeper
+ * idle states.
+ */
+static void __init omap4_smp_maybe_reset_cpu1(struct omap_smp_config *c)
+{
+ unsigned long cpu1_startup_pa, cpu1_ns_pa_addr;
+ bool needs_reset = false;
+ u32 released;
+
+ if (omap_secure_apis_support())
+ released = omap_read_auxcoreboot0() & AUX_CORE_BOOT0_HS_RELEASE;
+ else
+ released = readl_relaxed(cfg.wakeupgen_base +
+ OMAP_AUX_CORE_BOOT_0) &
+ AUX_CORE_BOOT0_GP_RELEASE;
+ if (released) {
+ pr_warn("smp: CPU1 not parked?\n");
+
+ return;
+ }
+
+ cpu1_startup_pa = readl_relaxed(cfg.wakeupgen_base +
+ OMAP_AUX_CORE_BOOT_1);
+ cpu1_ns_pa_addr = omap4_get_cpu1_ns_pa_addr();
+
+ /* Did the configured secondary_startup() get overwritten? */
+ if (!omap4_smp_cpu1_startup_valid(cpu1_startup_pa))
+ needs_reset = true;
+
+ /*
+ * If omap4 or 5 has NS_PA_ADDR configured, CPU1 may be in a
+ * deeper idle state in WFI and will wake to an invalid address.
+ */
+ if ((soc_is_omap44xx() || soc_is_omap54xx()) &&
+ !omap4_smp_cpu1_startup_valid(cpu1_ns_pa_addr))
+ needs_reset = true;
+
+ if (!needs_reset || !c->cpu1_rstctrl_va)
+ return;
+
+ pr_info("smp: CPU1 parked within kernel, needs reset (0x%lx 0x%lx)\n",
+ cpu1_startup_pa, cpu1_ns_pa_addr);
+
+ writel_relaxed(1, c->cpu1_rstctrl_va);
+ readl_relaxed(c->cpu1_rstctrl_va);
+ writel_relaxed(0, c->cpu1_rstctrl_va);
+}
+
static void __init omap4_smp_prepare_cpus(unsigned int max_cpus)
{
- void __iomem *base = omap_get_wakeupgen_base();
const struct omap_smp_config *c = NULL;
if (soc_is_omap443x())
@@ -281,6 +350,7 @@ static void __init omap4_smp_prepare_cpus(unsigned int max_cpus)
/* Must preserve cfg.scu_base set earlier */
cfg.cpu1_rstctrl_pa = c->cpu1_rstctrl_pa;
cfg.startup_addr = c->startup_addr;
+ cfg.wakeupgen_base = omap_get_wakeupgen_base();
if (soc_is_dra74x() || soc_is_omap54xx()) {
if ((__boot_cpu_mode & MODE_MASK) == HYP_MODE)
@@ -299,15 +369,7 @@ static void __init omap4_smp_prepare_cpus(unsigned int max_cpus)
if (cfg.scu_base)
scu_enable(cfg.scu_base);
- /*
- * Reset CPU1 before configuring, otherwise kexec will
- * end up trying to use old kernel startup address.
- */
- if (cfg.cpu1_rstctrl_va) {
- writel_relaxed(1, cfg.cpu1_rstctrl_va);
- readl_relaxed(cfg.cpu1_rstctrl_va);
- writel_relaxed(0, cfg.cpu1_rstctrl_va);
- }
+ omap4_smp_maybe_reset_cpu1(&cfg);
/*
* Write the address of secondary startup routine into the
@@ -319,7 +381,7 @@ static void __init omap4_smp_prepare_cpus(unsigned int max_cpus)
omap_auxcoreboot_addr(__pa_symbol(cfg.startup_addr));
else
writel_relaxed(__pa_symbol(cfg.startup_addr),
- base + OMAP_AUX_CORE_BOOT_1);
+ cfg.wakeupgen_base + OMAP_AUX_CORE_BOOT_1);
}
const struct smp_operations omap4_smp_ops __initconst = {
--
2.11.1
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