[PATCH 0/4] ARM: v7-A !MMU support, CONFIG_VECTORS_BASE removal (almost)

[PATCH 0/4] ARM: v7-A !MMU support, CONFIG_VECTORS_BASE removal (almost)

[afzal mohammed]

Hi,

ARM core changes to support !MMU Kernel on v7-A MMU processors. This
series also does the preparation for CONFIG_VECTORS_BASE removal.

Based on the feedback from Russell on the initial patches (part RFC),
it was decided to handle vector base dynamically in C & work towards
the the goal of removing VECTORS_BASE from Kconfig. MMU platform's
always have exception base address at 0xffff0000, while no-MMU CP15
scenario was handled dynamically in C. Hivecs handling for no-MMU CP15
that was done in asm has been moved to C as part of dynamic handling.
This now leaves only vector region setup, used by Cortex-R, to be made
devoid of VECTORS_BASE so as to remove it from Kconfig.

Vladimir is planning to rework MPU code, so it has been left untouched.
VECTORS_BASE is to be removed from Kconfig after the MPU region rework.

This series has been tested on top of mainline on,
1. Vybrid CM4 (!MMU)
2. Vybrid CA5 (MMU)

and on top of Vladimir's series[1] on,
1. Vybrid CM4 (!MMU)
2. Vybrid CA5 (MMU & !MMU)
3. AM437x IDK (MMU & !MMU)

Both above had an additional patch [2] as well, which is in next now.

Regards
afzal

[1] "[RFC v2 PATCH 00/23] Allow NOMMU for MULTIPLATFORM",
    http://lists.infradead.org/pipermail/linux-arm-kernel/2016-November/470966.html
    (git://linux-arm.org/linux-vm.git nommu-rfc-v2)

[2] "[PATCH 1/2] ARM: nommu: allow enabling REMAP_VECTORS_TO_RAM"
    http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473593.html

afzal mohammed (4):
  ARM: mmu: decouple VECTORS_BASE from Kconfig
  ARM: nommu: dynamic exception base address setting
  ARM: nommu: display vectors base
  ARM: nommu: remove Hivecs configuration is asm

 arch/arm/include/asm/memory.h  |  2 ++
 arch/arm/kernel/head-nommu.S   |  5 ----
 arch/arm/mach-berlin/platsmp.c |  3 +-
 arch/arm/mm/dump.c             |  5 ++--
 arch/arm/mm/init.c             |  9 ++++--
 arch/arm/mm/mm.h               |  5 ++--
 arch/arm/mm/nommu.c            | 64 ++++++++++++++++++++++++++++++++++++++++--
 7 files changed, 79 insertions(+), 14 deletions(-)

-- 
2.11.0

[PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[afzal mohammed]

For MMU configurations, VECTORS_BASE is always 0xffff0000, a macro
definition will suffice.

Once exception address is handled dynamically for no-MMU also (this
would involve taking care of region setup too), VECTORS_BASE can be
removed from Kconfig.

Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
---

Though there was no build error without inclusion of asm/memory.h, to
be on the safer side it has been added, to reduce chances of build
breakage in random configurations.

 arch/arm/include/asm/memory.h  | 2 ++
 arch/arm/mach-berlin/platsmp.c | 3 ++-
 arch/arm/mm/dump.c             | 5 +++--
 arch/arm/mm/init.c             | 4 ++--
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 76cbd9c674df..9cc9f1dbc88e 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -83,6 +83,8 @@
 #define IOREMAP_MAX_ORDER	24
 #endif
 
+#define VECTORS_BASE		0xffff0000
+
 #else /* CONFIG_MMU */
 
 /*
diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c
index 93f90688db18..578d41031abf 100644
--- a/arch/arm/mach-berlin/platsmp.c
+++ b/arch/arm/mach-berlin/platsmp.c
@@ -15,6 +15,7 @@
 
 #include <asm/cacheflush.h>
 #include <asm/cp15.h>
+#include <asm/memory.h>
 #include <asm/smp_plat.h>
 #include <asm/smp_scu.h>
 
@@ -75,7 +76,7 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
 	if (!cpu_ctrl)
 		goto unmap_scu;
 
-	vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);
+	vectors_base = ioremap(VECTORS_BASE, SZ_32K);
 	if (!vectors_base)
 		goto unmap_scu;
 
diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 9fe8e241335c..21192d6eda40 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -18,6 +18,7 @@
 #include <linux/seq_file.h>
 
 #include <asm/fixmap.h>
+#include <asm/memory.h>
 #include <asm/pgtable.h>
 
 struct addr_marker {
@@ -31,8 +32,8 @@ static struct addr_marker address_markers[] = {
 	{ 0,			"vmalloc() Area" },
 	{ VMALLOC_END,		"vmalloc() End" },
 	{ FIXADDR_START,	"Fixmap Area" },
-	{ CONFIG_VECTORS_BASE,	"Vectors" },
-	{ CONFIG_VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
+	{ VECTORS_BASE,	"Vectors" },
+	{ VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
 	{ -1,			NULL },
 };
 
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 370581aeb871..cf47f86f79ed 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -27,6 +27,7 @@
 #include <asm/cp15.h>
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
+#include <asm/memory.h>
 #include <asm/prom.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -521,8 +522,7 @@ void __init mem_init(void)
 			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
 			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
 
-			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
-				(PAGE_SIZE)),
+			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
 #ifdef CONFIG_HAVE_TCM
 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
-- 
2.11.0

[PATCH 2/4] ARM: nommu: dynamic exception base address setting

[afzal mohammed]

No-MMU dynamic exception base address configuration on CP15
processors. In the case of low vectors, decision based on whether
security extensions are enabled & whether remap vectors to RAM
CONFIG option is selected.

For no-MMU without CP15, current default value of 0x0 is retained.

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
---
 arch/arm/mm/nommu.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 2740967727e2..db8e784f20f3 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 
 #include <asm/cacheflush.h>
+#include <asm/cp15.h>
 #include <asm/sections.h>
 #include <asm/page.h>
 #include <asm/setup.h>
@@ -22,6 +23,8 @@
 
 #include "mm.h"
 
+unsigned long vectors_base;
+
 #ifdef CONFIG_ARM_MPU
 struct mpu_rgn_info mpu_rgn_info;
 
@@ -278,15 +281,72 @@ static void sanity_check_meminfo_mpu(void) {}
 static void __init mpu_setup(void) {}
 #endif /* CONFIG_ARM_MPU */
 
+#ifdef CONFIG_CPU_CP15
+#ifdef CONFIG_CPU_HIGH_VECTOR
+static unsigned long __init setup_vectors_base(void)
+{
+	unsigned long reg = get_cr();
+
+	set_cr(reg | CR_V);
+	return 0xffff0000;
+}
+#else /* CONFIG_CPU_HIGH_VECTOR */
+/*
+ * ID_PRF1 bits (CP#15 ID_PFR1)
+ */
+#define ID_PFR1_SE (0x3 << 4)	/* Security extension enable bits */
+
+/* Read processor feature register ID_PFR1 */
+static unsigned long get_id_pfr1(void)
+{
+	unsigned long val;
+
+	asm("mrc p15, 0, %0, c0, c1, 1" : "=r" (val) : : "cc");
+	return val;
+}
+
+/* Write exception base address to VBAR */
+static void set_vbar(unsigned long val)
+{
+	asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
+}
+
+static bool __init security_extensions_enabled(void)
+{
+	return !!(get_id_pfr1() & ID_PFR1_SE);
+}
+
+static unsigned long __init setup_vectors_base(void)
+{
+	unsigned long base = 0, reg = get_cr();
+
+	set_cr(reg & ~CR_V);
+	if (security_extensions_enabled()) {
+		if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
+			base = CONFIG_DRAM_BASE;
+		set_vbar(base);
+	} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
+		if (CONFIG_DRAM_BASE != 0)
+			pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
+	}
+
+	return base;
+}
+#endif /* CONFIG_CPU_HIGH_VECTOR */
+#endif /* CONFIG_CPU_CP15 */
+
 void __init arm_mm_memblock_reserve(void)
 {
 #ifndef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_CP15
+	vectors_base = setup_vectors_base();
+#endif
 	/*
 	 * Register the exception vector page.
 	 * some architectures which the DRAM is the exception vector to trap,
 	 * alloc_page breaks with error, although it is not NULL, but "0."
 	 */
-	memblock_reserve(CONFIG_VECTORS_BASE, 2 * PAGE_SIZE);
+	memblock_reserve(vectors_base, 2 * PAGE_SIZE);
 #else /* ifndef CONFIG_CPU_V7M */
 	/*
 	 * There is no dedicated vector page on V7-M. So nothing needs to be
@@ -310,7 +370,7 @@ void __init sanity_check_meminfo(void)
  */
 void __init paging_init(const struct machine_desc *mdesc)
 {
-	early_trap_init((void *)CONFIG_VECTORS_BASE);
+	early_trap_init((void *)vectors_base);
 	mpu_setup();
 	bootmem_init();
 }
-- 
2.11.0

[PATCH 3/4] ARM: nommu: display vectors base

[afzal mohammed]

The exception base address is now dynamically estimated for no-MMU
case, display it.

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
---
 arch/arm/mm/init.c | 5 +++++
 arch/arm/mm/mm.h   | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index cf47f86f79ed..9e11f255c3bf 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -522,7 +522,12 @@ void __init mem_init(void)
 			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
 			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
 
+#ifdef CONFIG_MMU
 			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
+#else
+			MLK_ROUNDUP(vectors_base, vectors_base + PAGE_SIZE),
+#endif
+
 #ifdef CONFIG_HAVE_TCM
 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index ce727d47275c..546f09437fca 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -79,8 +79,9 @@ struct static_vm {
 extern struct list_head static_vmlist;
 extern struct static_vm *find_static_vm_vaddr(void *vaddr);
 extern __init void add_static_vm_early(struct static_vm *svm);
-
-#endif
+#else /* CONFIG_MMU */
+extern unsigned long vectors_base;
+#endif /* CONFIG_MMU */
 
 #ifdef CONFIG_ZONE_DMA
 extern phys_addr_t arm_dma_limit;
-- 
2.11.0

[PATCH 4/4] ARM: nommu: remove Hivecs configuration is asm

[afzal mohammed]

Now that exception based address is handled dynamically for
processors with CP15, remove Highvecs configuration in assembly.

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
---
 arch/arm/kernel/head-nommu.S | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 6b4eb27b8758..2e21e08de747 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -152,11 +152,6 @@ __after_proc_init:
 #ifdef CONFIG_CPU_ICACHE_DISABLE
 	bic	r0, r0, #CR_I
 #endif
-#ifdef CONFIG_CPU_HIGH_VECTOR
-	orr	r0, r0, #CR_V
-#else
-	bic	r0, r0, #CR_V
-#endif
 	mcr	p15, 0, r0, c1, c0, 0		@ write control reg
 #elif defined (CONFIG_CPU_V7M)
 	/* For V7M systems we want to modify the CCR similarly to the SCTLR */
-- 
2.11.0

Re: [PATCH 3/4] ARM: nommu: display vectors base

[Russell King - ARM Linux]

On Thu, Jan 19, 2017 at 02:08:37AM +0530, afzal mohammed wrote:
> The exception base address is now dynamically estimated for no-MMU
> case, display it.
> 
> Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
> ---
>  arch/arm/mm/init.c | 5 +++++
>  arch/arm/mm/mm.h   | 5 +++--
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index cf47f86f79ed..9e11f255c3bf 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -522,7 +522,12 @@ void __init mem_init(void)
>  			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
>  			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
>  
> +#ifdef CONFIG_MMU
>  			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
> +#else
> +			MLK_ROUNDUP(vectors_base, vectors_base + PAGE_SIZE),

I think MLK() will do here - no need to use the rounding-up version
as PAGE_SIZE is a multiple of 1k.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 3/4] ARM: nommu: display vectors base

[Afzal Mohammed]

Hi,

On Wed, Jan 18, 2017 at 10:13:15PM +0000, Russell King - ARM Linux wrote:
> On Thu, Jan 19, 2017 at 02:08:37AM +0530, afzal mohammed wrote:

> > +			MLK_ROUNDUP(vectors_base, vectors_base + PAGE_SIZE),
> 
> I think MLK() will do here - no need to use the rounding-up version
> as PAGE_SIZE is a multiple of 1k.

Yes, i will replace it.

Earlier, used MLK(), got some build error, now checking again, no
build error, i should have messed up something at that time.

Regards
afzal

Re: [PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[Afzal Mohammed]

+ Marvell Berlin SoC maintainers - Sebastian, Jisheng

On Thu, Jan 19, 2017 at 02:07:39AM +0530, afzal mohammed wrote:
> For MMU configurations, VECTORS_BASE is always 0xffff0000, a macro
> definition will suffice.
> 
> Once exception address is handled dynamically for no-MMU also (this
> would involve taking care of region setup too), VECTORS_BASE can be
> removed from Kconfig.
> 
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
> ---
> 
> Though there was no build error without inclusion of asm/memory.h, to
> be on the safer side it has been added, to reduce chances of build
> breakage in random configurations.
> 
>  arch/arm/include/asm/memory.h  | 2 ++
>  arch/arm/mach-berlin/platsmp.c | 3 ++-
>  arch/arm/mm/dump.c             | 5 +++--
>  arch/arm/mm/init.c             | 4 ++--
>  4 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index 76cbd9c674df..9cc9f1dbc88e 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -83,6 +83,8 @@
>  #define IOREMAP_MAX_ORDER	24
>  #endif
>  
> +#define VECTORS_BASE		0xffff0000
> +
>  #else /* CONFIG_MMU */
>  
>  /*
> diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c
> index 93f90688db18..578d41031abf 100644
> --- a/arch/arm/mach-berlin/platsmp.c
> +++ b/arch/arm/mach-berlin/platsmp.c
> @@ -15,6 +15,7 @@
>  
>  #include <asm/cacheflush.h>
>  #include <asm/cp15.h>
> +#include <asm/memory.h>
>  #include <asm/smp_plat.h>
>  #include <asm/smp_scu.h>
>  
> @@ -75,7 +76,7 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
>  	if (!cpu_ctrl)
>  		goto unmap_scu;
>  
> -	vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);
> +	vectors_base = ioremap(VECTORS_BASE, SZ_32K);
>  	if (!vectors_base)
>  		goto unmap_scu;
>  
> diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
> index 9fe8e241335c..21192d6eda40 100644
> --- a/arch/arm/mm/dump.c
> +++ b/arch/arm/mm/dump.c
> @@ -18,6 +18,7 @@
>  #include <linux/seq_file.h>
>  
>  #include <asm/fixmap.h>
> +#include <asm/memory.h>
>  #include <asm/pgtable.h>
>  
>  struct addr_marker {
> @@ -31,8 +32,8 @@ static struct addr_marker address_markers[] = {
>  	{ 0,			"vmalloc() Area" },
>  	{ VMALLOC_END,		"vmalloc() End" },
>  	{ FIXADDR_START,	"Fixmap Area" },
> -	{ CONFIG_VECTORS_BASE,	"Vectors" },
> -	{ CONFIG_VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
> +	{ VECTORS_BASE,	"Vectors" },
> +	{ VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
>  	{ -1,			NULL },
>  };
>  
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index 370581aeb871..cf47f86f79ed 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -27,6 +27,7 @@
>  #include <asm/cp15.h>
>  #include <asm/mach-types.h>
>  #include <asm/memblock.h>
> +#include <asm/memory.h>
>  #include <asm/prom.h>
>  #include <asm/sections.h>
>  #include <asm/setup.h>
> @@ -521,8 +522,7 @@ void __init mem_init(void)
>  			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
>  			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
>  
> -			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
> -				(PAGE_SIZE)),
> +			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
>  #ifdef CONFIG_HAVE_TCM
>  			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
>  			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
> -- 
> 2.11.0

Re: [PATCH 2/4] ARM: nommu: dynamic exception base address setting

[Vladimir Murzin]

Hi,

On 18/01/17 20:38, afzal mohammed wrote:
> No-MMU dynamic exception base address configuration on CP15
> processors. In the case of low vectors, decision based on whether
> security extensions are enabled & whether remap vectors to RAM
> CONFIG option is selected.
> 
> For no-MMU without CP15, current default value of 0x0 is retained.
> 
> Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
> ---
>  arch/arm/mm/nommu.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 62 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
> index 2740967727e2..db8e784f20f3 100644
> --- a/arch/arm/mm/nommu.c
> +++ b/arch/arm/mm/nommu.c
> @@ -11,6 +11,7 @@
>  #include <linux/kernel.h>
>  
>  #include <asm/cacheflush.h>
> +#include <asm/cp15.h>
>  #include <asm/sections.h>
>  #include <asm/page.h>
>  #include <asm/setup.h>
> @@ -22,6 +23,8 @@
>  
>  #include "mm.h"
>  
> +unsigned long vectors_base;
> +
>  #ifdef CONFIG_ARM_MPU
>  struct mpu_rgn_info mpu_rgn_info;
>  
> @@ -278,15 +281,72 @@ static void sanity_check_meminfo_mpu(void) {}
>  static void __init mpu_setup(void) {}
>  #endif /* CONFIG_ARM_MPU */
>  
> +#ifdef CONFIG_CPU_CP15
> +#ifdef CONFIG_CPU_HIGH_VECTOR
> +static unsigned long __init setup_vectors_base(void)
> +{
> +	unsigned long reg = get_cr();
> +
> +	set_cr(reg | CR_V);
> +	return 0xffff0000;
> +}
> +#else /* CONFIG_CPU_HIGH_VECTOR */
> +/*
> + * ID_PRF1 bits (CP#15 ID_PFR1)
> + */
> +#define ID_PFR1_SE (0x3 << 4)	/* Security extension enable bits */

This bitfiled is 4 bits wide.

> +
> +/* Read processor feature register ID_PFR1 */
> +static unsigned long get_id_pfr1(void)
> +{
> +	unsigned long val;
> +
> +	asm("mrc p15, 0, %0, c0, c1, 1" : "=r" (val) : : "cc");
> +	return val;
> +}
> +
> +/* Write exception base address to VBAR */
> +static void set_vbar(unsigned long val)
> +{
> +	asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
> +}
> +
> +static bool __init security_extensions_enabled(void)
> +{
> +	return !!(get_id_pfr1() & ID_PFR1_SE);
> +}
> +
> +static unsigned long __init setup_vectors_base(void)
> +{
> +	unsigned long base = 0, reg = get_cr();
> +
> +	set_cr(reg & ~CR_V);
> +	if (security_extensions_enabled()) {

You can use

    cpuid_feature_extract(CPUID_EXT_PFR1, 4)
    
and add a comment explaining what we are looking for and why.

> +		if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
> +			base = CONFIG_DRAM_BASE;
> +		set_vbar(base);
> +	} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
> +		if (CONFIG_DRAM_BASE != 0)
> +			pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
> +	}
> +
> +	return base;
> +}
> +#endif /* CONFIG_CPU_HIGH_VECTOR */
> +#endif /* CONFIG_CPU_CP15 */
> +
>  void __init arm_mm_memblock_reserve(void)
>  {
>  #ifndef CONFIG_CPU_V7M
> +#ifdef CONFIG_CPU_CP15
> +	vectors_base = setup_vectors_base();
> +#endif

alternatively it can be

	unsigned long vector_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vbar() : 0;


Thanks
Vladimir

>  	/*
>  	 * Register the exception vector page.
>  	 * some architectures which the DRAM is the exception vector to trap,
>  	 * alloc_page breaks with error, although it is not NULL, but "0."
>  	 */
> -	memblock_reserve(CONFIG_VECTORS_BASE, 2 * PAGE_SIZE);
> +	memblock_reserve(vectors_base, 2 * PAGE_SIZE);
>  #else /* ifndef CONFIG_CPU_V7M */
>  	/*
>  	 * There is no dedicated vector page on V7-M. So nothing needs to be
> @@ -310,7 +370,7 @@ void __init sanity_check_meminfo(void)
>   */
>  void __init paging_init(const struct machine_desc *mdesc)
>  {
> -	early_trap_init((void *)CONFIG_VECTORS_BASE);
> +	early_trap_init((void *)vectors_base);
>  	mpu_setup();
>  	bootmem_init();
>  }
> 

Re: [PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[kbuild test robot]

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Hi afzal,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.10-rc4 next-20170119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/afzal-mohammed/ARM-mmu-decouple-VECTORS_BASE-from-Kconfig/20170119-171424
config: arm-stm32_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

Note: the linux-review/afzal-mohammed/ARM-mmu-decouple-VECTORS_BASE-from-Kconfig/20170119-171424 HEAD dd110acc21d40c8f50374de1e500a091d14f29c8 builds fine.
      It only hurts bisectibility.

All error/warnings (new ones prefixed by >>):

   arch/arm/mm/init.c: In function 'mem_init':
>> arch/arm/mm/init.c:525:11: error: 'VECTORS_BASEUL' undeclared (first use in this function)
       MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
              ^
   arch/arm/mm/init.c:501:19: note: in definition of macro 'MLK'
    #define MLK(b, t) b, t, ((t) - (b)) >> 10
                      ^
>> include/uapi/linux/const.h:20:18: note: in expansion of macro '__AC'
    #define _AC(X,Y) __AC(X,Y)
                     ^~~~
>> arch/arm/include/asm/memory.h:29:15: note: in expansion of macro '_AC'
    #define UL(x) _AC(x, UL)
                  ^~~
>> include/linux/printk.h:297:36: note: in expansion of macro 'UL'
     printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
                                       ^~~~~~~~~~~
>> arch/arm/mm/init.c:505:2: note: in expansion of macro 'pr_notice'
     pr_notice("Virtual kernel memory layout:\n"
     ^~~~~~~~~
   arch/arm/mm/init.c:525:11: note: each undeclared identifier is reported only once for each function it appears in
       MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
              ^
   arch/arm/mm/init.c:501:19: note: in definition of macro 'MLK'
    #define MLK(b, t) b, t, ((t) - (b)) >> 10
                      ^
>> include/uapi/linux/const.h:20:18: note: in expansion of macro '__AC'
    #define _AC(X,Y) __AC(X,Y)
                     ^~~~
>> arch/arm/include/asm/memory.h:29:15: note: in expansion of macro '_AC'
    #define UL(x) _AC(x, UL)
                  ^~~
>> include/linux/printk.h:297:36: note: in expansion of macro 'UL'
     printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
                                       ^~~~~~~~~~~
>> arch/arm/mm/init.c:505:2: note: in expansion of macro 'pr_notice'
     pr_notice("Virtual kernel memory layout:\n"
     ^~~~~~~~~

vim +/VECTORS_BASEUL +525 arch/arm/mm/init.c

   499		mem_init_print_info(NULL);
   500	
   501	#define MLK(b, t) b, t, ((t) - (b)) >> 10
   502	#define MLM(b, t) b, t, ((t) - (b)) >> 20
   503	#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
   504	
 > 505		pr_notice("Virtual kernel memory layout:\n"
   506				"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
   507	#ifdef CONFIG_HAVE_TCM
   508				"    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
   509				"    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
   510	#endif
   511				"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
   512				"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
   513				"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
   514	#ifdef CONFIG_HIGHMEM
   515				"    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
   516	#endif
   517	#ifdef CONFIG_MODULES
   518				"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
   519	#endif
   520				"      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
   521				"      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
   522				"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
   523				"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
   524	
 > 525				MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
   526	#ifdef CONFIG_HAVE_TCM
   527				MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
   528				MLK(ITCM_OFFSET, (unsigned long) itcm_end),

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 8634 bytes --]

Re: [PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[Russell King - ARM Linux]

On Thu, Jan 19, 2017 at 02:07:39AM +0530, afzal mohammed wrote:
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index 76cbd9c674df..9cc9f1dbc88e 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -83,6 +83,8 @@
>  #define IOREMAP_MAX_ORDER	24
>  #endif
>  
> +#define VECTORS_BASE		0xffff0000

This should be UL(0xffff0000)

> -			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
> -				(PAGE_SIZE)),
> +			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),

which means you don't need it here, which will then fix the build error
reported by the 0-day builder.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[Afzal Mohammed]

Hi,

On Thu, Jan 19, 2017 at 02:24:24PM +0000, Russell King - ARM Linux wrote:
> On Thu, Jan 19, 2017 at 02:07:39AM +0530, afzal mohammed wrote:

> > +++ b/arch/arm/include/asm/memory.h

> > +#define VECTORS_BASE		0xffff0000
> 
> This should be UL(0xffff0000)

> > -			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
> > -				(PAGE_SIZE)),
> > +			MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
> 
> which means you don't need it here, which will then fix the build error
> reported by the 0-day builder.

Seems there is some confusion here,

VECTORS_BASE definition above in memory.h is enclosed within
CONFIG_MMU. Robot used a no-MMU defconfig, it didn't get a
VECTORS_BASE definition at this patch, causing the build error. Our
dear robot mentioned that my HEAD didn't break build, but
bisectability is broken at this point.

With "PATCH 3/4 ARM: nommu: display vectors base", the above is
changed to
        #ifdef CONFIG_MMU
                MLK(UL(VECTORS_BASE), UL(VECTORS_BASE) + (PAGE_SIZE)),
        #else
                ...
        #endif
thus making the series build again for no-MMU

One option to keep bisectability would be to squash this with PATCH
3/4, but i think a better & natural solution would be define
VECTORS_BASE outside of
        #ifdef CONFIG_MMU
        ...
        #else
        ...
        #endif
and then in PATCH 3/4, move VECTORS_BASE to be inside
        #ifdef CONFIG_MMU
        ...
        #else

Regards
afzal

Re: [PATCH 2/4] ARM: nommu: dynamic exception base address setting

[Afzal Mohammed]

Hi,

On Thu, Jan 19, 2017 at 01:59:09PM +0000, Vladimir Murzin wrote:
> On 18/01/17 20:38, afzal mohammed wrote:

> > +#define ID_PFR1_SE (0x3 << 4)	/* Security extension enable bits */
> 
> This bitfiled is 4 bits wide.

Since only 2 LSb's out of the 4 were enough to detect whether security
extensions were enabled, it was done so. i am going to use your below
suggestion & this would be taken care by that.

> > +	if (security_extensions_enabled()) {
> 
> You can use
> 
>     cpuid_feature_extract(CPUID_EXT_PFR1, 4)
>     
> and add a comment explaining what we are looking for and why.

Yes, that is better, was not aware of this, did saw CPUID_EXT_PFR1 as
an unused macro.

> > +#ifdef CONFIG_CPU_CP15
> > +	vectors_base = setup_vectors_base();
> > +#endif
> 
> alternatively it can be
> 
> 	unsigned long vector_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vbar() : 0;

Yes that certainly is better.

Regards
afzal

Re: [PATCH 1/4] ARM: mmu: decouple VECTORS_BASE from Kconfig

[Afzal Mohammed]

Hi,

On Thu, Jan 19, 2017 at 02:24:24PM +0000, Russell King - ARM Linux wrote:
> On Thu, Jan 19, 2017 at 02:07:39AM +0530, afzal mohammed wrote:

> > +#define VECTORS_BASE		0xffff0000
> 
> This should be UL(0xffff0000)

This has been taken care in v2.

Regards
afzal

Re: [PATCH 2/4] ARM: nommu: dynamic exception base address setting

[Afzal Mohammed]

Hi,

On Fri, Jan 20, 2017 at 09:50:22PM +0530, Afzal Mohammed wrote:
> On Thu, Jan 19, 2017 at 01:59:09PM +0000, Vladimir Murzin wrote:

> > You can use
> > 
> >     cpuid_feature_extract(CPUID_EXT_PFR1, 4)
> >     
> > and add a comment explaining what we are looking for and why.

W.r.t comments, tried to keep it concise, C tokens doing a part of it.

> Yes, that is better, was not aware of this, did saw CPUID_EXT_PFR1 as
> an unused macro.

> > > +#ifdef CONFIG_CPU_CP15
> > > +	vectors_base = setup_vectors_base();
> > > +#endif
> > 
> > alternatively it can be
> > 
> > 	unsigned long vector_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vbar() : 0;
> 
> Yes that certainly is better.

Have kept the function name as setup_vector_base() as in addition to
setting up VBAR, V bit also has to be configured by it - so that
function name remains true to it's name.

v2 with changes has been posted.

Regards
afzal

Re: [PATCH 3/4] ARM: nommu: display vectors base

[Russell King - ARM Linux]

On Thu, Jan 19, 2017 at 06:46:32PM +0530, Afzal Mohammed wrote:
> Hi,
> 
> On Wed, Jan 18, 2017 at 10:13:15PM +0000, Russell King - ARM Linux wrote:
> > On Thu, Jan 19, 2017 at 02:08:37AM +0530, afzal mohammed wrote:
> 
> > > +			MLK_ROUNDUP(vectors_base, vectors_base + PAGE_SIZE),
> > 
> > I think MLK() will do here - no need to use the rounding-up version
> > as PAGE_SIZE is a multiple of 1k.
> 
> Yes, i will replace it.
> 
> Earlier, used MLK(), got some build error, now checking again, no
> build error, i should have messed up something at that time.

Sorry for the delayed response.

With that change, you can get rid of this preprocessor conditional.
Arrange to have VECTORS_BASE defined to vectors_base in the nommu
part of asm/memory.h.  You'll also need to move the extern of that
there too.

Thanks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.