[PATCH v9 20/22] powerpc: Enable HAVE_ARCH_NVRAM_OPS and disable GENERIC_NVRAM

Finn Thain
2019-01-15T04:23:18Z

Switch PPC32 kernels from the generic_nvram module to the nvram module.

Also fix a theoretical bug where CHRP omits the chrp_nvram_init() call
when CONFIG_NVRAM_MODULE=m.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
The change in the name of the module is visible to userspace. The module
that implements /dev/nvram on PowerPC now has suitable aliases, i.e.
MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
MODULE_ALIAS("devname:nvram");
so that the device special file can be automatically created and the
module automatically loaded when needed. Previously this was not the case.

Changed since v8:
- Moved the HAVE_ARCH_NVRAM_OPS symbol to common code as suggested by
Christoph Hellwig.
- Changed arch_nvram_ops method calls to ppc_md method calls.
- Removed the now unused nvram_sync() export.

Changed since v7:
- Improved Kconfig help text for CONFIG_NVRAM.
- Changed the default for CONFIG_NVRAM, which used to be "n". This is to
reduce the risk that CONFIG_GENERIC_NVRAM=y accidentally gets changed to
CONFIG_NVRAM=n.
---
arch/powerpc/Kconfig | 6 +-----
arch/powerpc/include/asm/nvram.h | 3 ---
arch/powerpc/kernel/setup_32.c | 11 -----------
arch/powerpc/platforms/chrp/Makefile | 2 +-
arch/powerpc/platforms/chrp/setup.c | 2 +-
arch/powerpc/platforms/powermac/setup.c | 3 +--
drivers/char/Kconfig | 19 +++++++++----------
include/linux/nvram.h | 20 ++++++++++++++++++++
8 files changed, 33 insertions(+), 33 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2890d36eb531..f62e6a3f9c4e 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -178,6 +178,7 @@ config PPC
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
+ select HAVE_ARCH_NVRAM_OPS if PPC32
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_CBPF_JIT if !PPC64
@@ -274,11 +275,6 @@ config SYSVIPC_COMPAT
depends on COMPAT && SYSVIPC
default y

-# All PPC32s use generic nvram driver through ppc_md
-config GENERIC_NVRAM
- bool
- default y if PPC32
-
config SCHED_OMIT_FRAME_POINTER
bool
default y
diff --git a/arch/powerpc/include/asm/nvram.h b/arch/powerpc/include/asm/nvram.h
index 56a388da9c4f..629a5cdcc865 100644
--- a/arch/powerpc/include/asm/nvram.h
+++ b/arch/powerpc/include/asm/nvram.h
@@ -78,9 +78,6 @@ extern int pmac_get_partition(int partition);
extern u8 pmac_xpram_read(int xpaddr);
extern void pmac_xpram_write(int xpaddr, u8 data);

-/* Synchronize NVRAM */
-extern void nvram_sync(void);
-
/* Initialize NVRAM OS partition */
extern int __init nvram_init_os_partition(struct nvram_os_partition *part);

diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index f5107796e2d7..c31082233a25 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -148,17 +148,6 @@ static int __init ppc_setup_l3cr(char *str)
}
__setup("l3cr=", ppc_setup_l3cr);

-#ifdef CONFIG_GENERIC_NVRAM
-
-void nvram_sync(void)
-{
- if (ppc_md.nvram_sync)
- ppc_md.nvram_sync();
-}
-EXPORT_SYMBOL(nvram_sync);
-
-#endif /* CONFIG_NVRAM */
-
static int __init ppc_init(void)
{
/* clear the progress line */
diff --git a/arch/powerpc/platforms/chrp/Makefile b/arch/powerpc/platforms/chrp/Makefile
index 4b3bfadc70fa..dc3465cc8bc6 100644
--- a/arch/powerpc/platforms/chrp/Makefile
+++ b/arch/powerpc/platforms/chrp/Makefile
@@ -1,3 +1,3 @@
obj-y += setup.o time.o pegasos_eth.o pci.o
obj-$(CONFIG_SMP) += smp.o
-obj-$(CONFIG_NVRAM) += nvram.o
+obj-$(CONFIG_NVRAM:m=y) += nvram.o
diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index e66644e0fb40..e8e804289c8e 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -550,7 +550,7 @@ static void __init chrp_init_IRQ(void)
static void __init
chrp_init2(void)
{
-#ifdef CONFIG_NVRAM
+#if IS_ENABLED(CONFIG_NVRAM)
chrp_nvram_init();
#endif

diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 2e8221e20ee8..b47f49cf9c4d 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -316,8 +316,7 @@ static void __init pmac_setup_arch(void)
find_via_pmu();
smu_init();

-#if defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE) || \
- defined(CONFIG_PPC64)
+#if IS_ENABLED(CONFIG_NVRAM) || defined(CONFIG_PPC64)
pmac_nvram_init();
#endif
#ifdef CONFIG_PPC32
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index ce9979529cf3..72866a004f07 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -244,25 +244,24 @@ source "drivers/char/hw_random/Kconfig"

config NVRAM
tristate "/dev/nvram support"
- depends on X86 || GENERIC_NVRAM || HAVE_ARCH_NVRAM_OPS
- default M68K
+ depends on X86 || HAVE_ARCH_NVRAM_OPS
+ default M68K || PPC
---help---
If you say Y here and create a character special file /dev/nvram
with major number 10 and minor number 144 using mknod ("man mknod"),
- you get read and write access to the extra bytes of non-volatile
- memory in the real time clock (RTC), which is contained in every PC
- and most Ataris. The actual number of bytes varies, depending on the
- nvram in the system, but is usually 114 (128-14 for the RTC).
-
- This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
- on Ataris. /dev/nvram may be used to view settings there, or to
- change them (with some utility). It could also be used to frequently
+ you get read and write access to the non-volatile memory.
+
+ /dev/nvram may be used to view settings in NVRAM or to change them
+ (with some utility). It could also be used to frequently
save a few bits of very important data that may not be lost over
power-off and for which writing to disk is too insecure. Note
however that most NVRAM space in a PC belongs to the BIOS and you
should NEVER idly tamper with it. See Ralf Brown's interrupt list
for a guide to the use of CMOS bytes by your BIOS.

+ This memory is conventionally called "NVRAM" on PowerPC machines,
+ "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes.
+
To compile this driver as a module, choose M here: the
module will be called nvram.

diff --git a/include/linux/nvram.h b/include/linux/nvram.h
index 9e3a957c8f1f..d29d9c93a927 100644
--- a/include/linux/nvram.h
+++ b/include/linux/nvram.h
@@ -5,6 +5,10 @@
#include <linux/errno.h>
#include <uapi/linux/nvram.h>

+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
+
/**
* struct nvram_ops - NVRAM functionality made available to drivers
* @read: validate checksum (if any) then load a range of bytes from NVRAM
@@ -42,6 +46,8 @@ extern const struct nvram_ops arch_nvram_ops;
static inline ssize_t nvram_get_size(void)
{
#ifdef CONFIG_PPC
+ if (ppc_md.nvram_size)
+ return ppc_md.nvram_size();
#else
if (arch_nvram_ops.get_size)
return arch_nvram_ops.get_size();
@@ -52,6 +58,8 @@ static inline ssize_t nvram_get_size(void)
static inline unsigned char nvram_read_byte(int addr)
{
#ifdef CONFIG_PPC
+ if (ppc_md.nvram_read_val)
+ return ppc_md.nvram_read_val(addr);
#else
if (arch_nvram_ops.read_byte)
return arch_nvram_ops.read_byte(addr);
@@ -62,6 +70,8 @@ static inline unsigned char nvram_read_byte(int addr)
static inline void nvram_write_byte(unsigned char val, int addr)
{
#ifdef CONFIG_PPC
+ if (ppc_md.nvram_write_val)
+ ppc_md.nvram_write_val(addr, val);
#else
if (arch_nvram_ops.write_byte)
arch_nvram_ops.write_byte(val, addr);
@@ -98,15 +108,25 @@ static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos)

static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_read)
+ return ppc_md.nvram_read(buf, count, ppos);
+#else
if (arch_nvram_ops.read)
return arch_nvram_ops.read(buf, count, ppos);
+#endif
return nvram_read_bytes(buf, count, ppos);
}

static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_write)
+ return ppc_md.nvram_write(buf, count, ppos);
+#else
if (arch_nvram_ops.write)
return arch_nvram_ops.write(buf, count, ppos);
+#endif
return nvram_write_bytes(buf, count, ppos);
}

--
2.19.2