delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
the given starting address and size, from the device tree blob, and
removes the entry from the device tree blob. This function is called
to free the resources reserved for the buffer used for carrying forward
the IMA measurement logs on kexec. This function does not have
architecture specific code, but is currently limited to powerpc.
Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
accessible for other architectures as well.
Co-developed-by: Prakhar Srivastava <[email protected]>
Signed-off-by: Prakhar Srivastava <[email protected]>
Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
---
arch/powerpc/include/asm/kexec.h | 1 -
arch/powerpc/kexec/file_load.c | 32 -----------------
drivers/of/Makefile | 1 +
drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
include/linux/kexec.h | 5 +++
5 files changed, 67 insertions(+), 33 deletions(-)
create mode 100644 drivers/of/kexec.c
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 55d6ede30c19..7c223031ecdd 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
int setup_new_fdt(const struct kimage *image, void *fdt,
unsigned long initrd_load_addr, unsigned long initrd_len,
const char *cmdline);
-int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
#ifdef CONFIG_PPC64
struct kexec_buf;
diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
index 9a232bc36c8f..9efc98b1e2ae 100644
--- a/arch/powerpc/kexec/file_load.c
+++ b/arch/powerpc/kexec/file_load.c
@@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
return 0;
}
-/**
- * delete_fdt_mem_rsv - delete memory reservation with given address and size
- *
- * Return: 0 on success, or negative errno on error.
- */
-int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
-{
- int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
-
- for (i = 0; i < num_rsvs; i++) {
- uint64_t rsv_start, rsv_size;
-
- ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
- if (ret) {
- pr_err("Malformed device tree.\n");
- return -EINVAL;
- }
-
- if (rsv_start == start && rsv_size == size) {
- ret = fdt_del_mem_rsv(fdt, i);
- if (ret) {
- pr_err("Error deleting device tree reservation.\n");
- return -EINVAL;
- }
-
- return 0;
- }
- }
-
- return -ENOENT;
-}
-
/*
* setup_new_fdt - modify /chosen and memory reservation for the next kernel
* @image: kexec image being loaded.
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 6e1e5212f058..77d24712c0c8 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
obj-$(CONFIG_OF_RESOLVE) += resolver.o
obj-$(CONFIG_OF_OVERLAY) += overlay.o
obj-$(CONFIG_OF_NUMA) += of_numa.o
+obj-$(CONFIG_OF_FLATTREE) += kexec.o
obj-$(CONFIG_OF_UNITTEST) += unittest-data/
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
new file mode 100644
index 000000000000..b7d59105fcb8
--- /dev/null
+++ b/drivers/of/kexec.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Microsoft Corporation
+ *
+ * Author: Lakshmi Ramasubramanian ([email protected])
+ *
+ * File: kexec.c
+ * Defines kexec related functions.
+ */
+
+#define pr_fmt(fmt) "OF: kexec: " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+
+/**
+ * delete_fdt_mem_rsv - delete memory reservation with given address and size
+ *
+ * @fdt: Flattened Device Tree to update
+ * @start: Starting address of the reservation to delete
+ * @size: Size of the reservation to delete
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
+{
+ int i, ret, num_rsvs;
+
+ if (!IS_ENABLED(CONFIG_KEXEC_FILE))
+ return 0;
+
+ num_rsvs = fdt_num_mem_rsv(fdt);
+ for (i = 0; i < num_rsvs; i++) {
+ uint64_t rsv_start, rsv_size;
+
+ ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
+ if (ret) {
+ pr_err("Malformed device tree.\n");
+ return -EINVAL;
+ }
+
+ if (rsv_start == start && rsv_size == size) {
+ ret = fdt_del_mem_rsv(fdt, i);
+ if (ret) {
+ pr_err("Error deleting device tree reservation.\n");
+ return -EINVAL;
+ }
+
+ pr_debug("Freed reserved memory at %lu of size %lu\n",
+ start, size);
+ return 0;
+ }
+ }
+
+ return -ENOENT;
+}
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..d0234c4815da 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -407,6 +407,11 @@ static inline int kexec_crash_loaded(void) { return 0; }
#define kexec_in_progress false
#endif /* CONFIG_KEXEC_CORE */
+#if defined(CONFIG_OF_FLATTREE)
+extern int delete_fdt_mem_rsv(void *fdt, unsigned long start,
+ unsigned long size);
+#endif /* CONFIG_OF_FLATTREE */
+
#endif /* !defined(__ASSEBMLY__) */
#endif /* LINUX_KEXEC_H */
--
2.29.2
Hello Lakshmi,
Lakshmi Ramasubramanian <[email protected]> writes:
> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
> the given starting address and size, from the device tree blob, and
> removes the entry from the device tree blob. This function is called
> to free the resources reserved for the buffer used for carrying forward
> the IMA measurement logs on kexec. This function does not have
> architecture specific code, but is currently limited to powerpc.
>
> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
s/kexec_fdt.c/kexec.c/
> accessible for other architectures as well.
>
> Co-developed-by: Prakhar Srivastava <[email protected]>
> Signed-off-by: Prakhar Srivastava <[email protected]>
> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
> ---
> arch/powerpc/include/asm/kexec.h | 1 -
> arch/powerpc/kexec/file_load.c | 32 -----------------
> drivers/of/Makefile | 1 +
> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
> include/linux/kexec.h | 5 +++
> 5 files changed, 67 insertions(+), 33 deletions(-)
> create mode 100644 drivers/of/kexec.c
>
> diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
> index 55d6ede30c19..7c223031ecdd 100644
> --- a/arch/powerpc/include/asm/kexec.h
> +++ b/arch/powerpc/include/asm/kexec.h
> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
> int setup_new_fdt(const struct kimage *image, void *fdt,
> unsigned long initrd_load_addr, unsigned long initrd_len,
> const char *cmdline);
> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
>
> #ifdef CONFIG_PPC64
> struct kexec_buf;
> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
> index 9a232bc36c8f..9efc98b1e2ae 100644
> --- a/arch/powerpc/kexec/file_load.c
> +++ b/arch/powerpc/kexec/file_load.c
> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
> return 0;
> }
>
> -/**
> - * delete_fdt_mem_rsv - delete memory reservation with given address and size
> - *
> - * Return: 0 on success, or negative errno on error.
> - */
> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
> -{
> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
> -
> - for (i = 0; i < num_rsvs; i++) {
> - uint64_t rsv_start, rsv_size;
> -
> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
> - if (ret) {
> - pr_err("Malformed device tree.\n");
> - return -EINVAL;
> - }
> -
> - if (rsv_start == start && rsv_size == size) {
> - ret = fdt_del_mem_rsv(fdt, i);
> - if (ret) {
> - pr_err("Error deleting device tree reservation.\n");
> - return -EINVAL;
> - }
> -
> - return 0;
> - }
> - }
> -
> - return -ENOENT;
> -}
> -
> /*
> * setup_new_fdt - modify /chosen and memory reservation for the next kernel
> * @image: kexec image being loaded.
> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> index 6e1e5212f058..77d24712c0c8 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
> obj-$(CONFIG_OF_RESOLVE) += resolver.o
> obj-$(CONFIG_OF_OVERLAY) += overlay.o
> obj-$(CONFIG_OF_NUMA) += of_numa.o
> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
Isn't this too broad? kexec.o will only be useful to kernel configs
which enable CONFIG_KEXEC_FILE, so perhaps do:
ifdef CONFIG_OF_FLATTREE
ifdef CONFIG_KEXEC_FILE
obj-y += kexec.o
endif
endif
What do you think?
> obj-$(CONFIG_OF_UNITTEST) += unittest-data/
> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> new file mode 100644
> index 000000000000..b7d59105fcb8
> --- /dev/null
> +++ b/drivers/of/kexec.c
> @@ -0,0 +1,61 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020 Microsoft Corporation
> + *
> + * Author: Lakshmi Ramasubramanian ([email protected])
> + *
> + * File: kexec.c
> + * Defines kexec related functions.
> + */
> +
> +#define pr_fmt(fmt) "OF: kexec: " fmt
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/memblock.h>
> +#include <linux/kexec.h>
> +#include <linux/of.h>
> +#include <linux/of_fdt.h>
> +#include <linux/libfdt.h>
> +
> +/**
> + * delete_fdt_mem_rsv - delete memory reservation with given address and size
> + *
> + * @fdt: Flattened Device Tree to update
> + * @start: Starting address of the reservation to delete
> + * @size: Size of the reservation to delete
> + *
> + * Return: 0 on success, or negative errno on error.
> + */
> +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
> +{
> + int i, ret, num_rsvs;
> +
> + if (!IS_ENABLED(CONFIG_KEXEC_FILE))
> + return 0;
If you agree with my suggestion, then this IS_ENABLED() wouldn't be
needed.
> +
> + num_rsvs = fdt_num_mem_rsv(fdt);
> + for (i = 0; i < num_rsvs; i++) {
> + uint64_t rsv_start, rsv_size;
> +
> + ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
> + if (ret) {
> + pr_err("Malformed device tree.\n");
> + return -EINVAL;
> + }
> +
> + if (rsv_start == start && rsv_size == size) {
> + ret = fdt_del_mem_rsv(fdt, i);
> + if (ret) {
> + pr_err("Error deleting device tree reservation.\n");
> + return -EINVAL;
> + }
> +
> + pr_debug("Freed reserved memory at %lu of size %lu\n",
> + start, size);
> + return 0;
> + }
> + }
> +
> + return -ENOENT;
> +}
The function code is unchanged apart from the addition of the
IS_ENABLED() and the pr_debug(), so that is good.
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 9e93bef52968..d0234c4815da 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -407,6 +407,11 @@ static inline int kexec_crash_loaded(void) { return 0; }
> #define kexec_in_progress false
> #endif /* CONFIG_KEXEC_CORE */
>
> +#if defined(CONFIG_OF_FLATTREE)
This would also change to require CONFIG_KEXEC_FILE.
> +extern int delete_fdt_mem_rsv(void *fdt, unsigned long start,
> + unsigned long size);
> +#endif /* CONFIG_OF_FLATTREE */
> +
> #endif /* !defined(__ASSEBMLY__) */
>
> #endif /* LINUX_KEXEC_H */
--
Thiago Jung Bauermann
IBM Linux Technology Center
On 12/4/20 6:22 PM, Thiago Jung Bauermann wrote:
>
> Hello Lakshmi,
>
> Lakshmi Ramasubramanian <[email protected]> writes:
>
>> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
>> the given starting address and size, from the device tree blob, and
>> removes the entry from the device tree blob. This function is called
>> to free the resources reserved for the buffer used for carrying forward
>> the IMA measurement logs on kexec. This function does not have
>> architecture specific code, but is currently limited to powerpc.
>>
>> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
>
> s/kexec_fdt.c/kexec.c/
Missed that in the patch description. Will fix it. Thanks.
>> accessible for other architectures as well.
>>
>> Co-developed-by: Prakhar Srivastava <[email protected]>
>> Signed-off-by: Prakhar Srivastava <[email protected]>
>> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
>> ---
>> arch/powerpc/include/asm/kexec.h | 1 -
>> arch/powerpc/kexec/file_load.c | 32 -----------------
>> drivers/of/Makefile | 1 +
>> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
>> include/linux/kexec.h | 5 +++
>> 5 files changed, 67 insertions(+), 33 deletions(-)
>> create mode 100644 drivers/of/kexec.c
>>
>> diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
>> index 55d6ede30c19..7c223031ecdd 100644
>> --- a/arch/powerpc/include/asm/kexec.h
>> +++ b/arch/powerpc/include/asm/kexec.h
>> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
>> int setup_new_fdt(const struct kimage *image, void *fdt,
>> unsigned long initrd_load_addr, unsigned long initrd_len,
>> const char *cmdline);
>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
>>
>> #ifdef CONFIG_PPC64
>> struct kexec_buf;
>> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
>> index 9a232bc36c8f..9efc98b1e2ae 100644
>> --- a/arch/powerpc/kexec/file_load.c
>> +++ b/arch/powerpc/kexec/file_load.c
>> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
>> return 0;
>> }
>>
>> -/**
>> - * delete_fdt_mem_rsv - delete memory reservation with given address and size
>> - *
>> - * Return: 0 on success, or negative errno on error.
>> - */
>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
>> -{
>> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
>> -
>> - for (i = 0; i < num_rsvs; i++) {
>> - uint64_t rsv_start, rsv_size;
>> -
>> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>> - if (ret) {
>> - pr_err("Malformed device tree.\n");
>> - return -EINVAL;
>> - }
>> -
>> - if (rsv_start == start && rsv_size == size) {
>> - ret = fdt_del_mem_rsv(fdt, i);
>> - if (ret) {
>> - pr_err("Error deleting device tree reservation.\n");
>> - return -EINVAL;
>> - }
>> -
>> - return 0;
>> - }
>> - }
>> -
>> - return -ENOENT;
>> -}
>> -
>> /*
>> * setup_new_fdt - modify /chosen and memory reservation for the next kernel
>> * @image: kexec image being loaded.
>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>> index 6e1e5212f058..77d24712c0c8 100644
>> --- a/drivers/of/Makefile
>> +++ b/drivers/of/Makefile
>> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>> obj-$(CONFIG_OF_RESOLVE) += resolver.o
>> obj-$(CONFIG_OF_OVERLAY) += overlay.o
>> obj-$(CONFIG_OF_NUMA) += of_numa.o
>> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
>
> Isn't this too broad? kexec.o will only be useful to kernel configs
> which enable CONFIG_KEXEC_FILE, so perhaps do:
>
> ifdef CONFIG_OF_FLATTREE
> ifdef CONFIG_KEXEC_FILE
> obj-y += kexec.o
> endif
> endif
>
> What do you think?
Per Rob's feedback on v9 patch set, I have moved all the architecture
independent ima kexec functions to a single file "drivers/of/kexec.c"
Since these functions are enabled on different kernel CONFIGs, I have
used IS_ENABLED(CONFIG_XYZ) macro instead of "#ifdef" in the C file to
conditionally compile.
>
>> obj-$(CONFIG_OF_UNITTEST) += unittest-data/
>> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
>> new file mode 100644
>> index 000000000000..b7d59105fcb8
>> --- /dev/null
>> +++ b/drivers/of/kexec.c
>> @@ -0,0 +1,61 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright (C) 2020 Microsoft Corporation
>> + *
>> + * Author: Lakshmi Ramasubramanian ([email protected])
>> + *
>> + * File: kexec.c
>> + * Defines kexec related functions.
>> + */
>> +
>> +#define pr_fmt(fmt) "OF: kexec: " fmt
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/memblock.h>
>> +#include <linux/kexec.h>
>> +#include <linux/of.h>
>> +#include <linux/of_fdt.h>
>> +#include <linux/libfdt.h>
>> +
>> +/**
>> + * delete_fdt_mem_rsv - delete memory reservation with given address and size
>> + *
>> + * @fdt: Flattened Device Tree to update
>> + * @start: Starting address of the reservation to delete
>> + * @size: Size of the reservation to delete
>> + *
>> + * Return: 0 on success, or negative errno on error.
>> + */
>> +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
>> +{
>> + int i, ret, num_rsvs;
>> +
>> + if (!IS_ENABLED(CONFIG_KEXEC_FILE))
>> + return 0;
>
> If you agree with my suggestion, then this IS_ENABLED() wouldn't be
> needed.
>
Please see my response above.
If there is a way to keep all the ima kexec functions in a single file
and yet not use "#ifdef" in C file to conditionally compile, please let
me know. I'll update.
thanks,
-lakshmi
>> +
>> + num_rsvs = fdt_num_mem_rsv(fdt);
>> + for (i = 0; i < num_rsvs; i++) {
>> + uint64_t rsv_start, rsv_size;
>> +
>> + ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>> + if (ret) {
>> + pr_err("Malformed device tree.\n");
>> + return -EINVAL;
>> + }
>> +
>> + if (rsv_start == start && rsv_size == size) {
>> + ret = fdt_del_mem_rsv(fdt, i);
>> + if (ret) {
>> + pr_err("Error deleting device tree reservation.\n");
>> + return -EINVAL;
>> + }
>> +
>> + pr_debug("Freed reserved memory at %lu of size %lu\n",
>> + start, size);
>> + return 0;
>> + }
>> + }
>> +
>> + return -ENOENT;
>> +}
>
> The function code is unchanged apart from the addition of the
> IS_ENABLED() and the pr_debug(), so that is good.
>
>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>> index 9e93bef52968..d0234c4815da 100644
>> --- a/include/linux/kexec.h
>> +++ b/include/linux/kexec.h
>> @@ -407,6 +407,11 @@ static inline int kexec_crash_loaded(void) { return 0; }
>> #define kexec_in_progress false
>> #endif /* CONFIG_KEXEC_CORE */
>>
>> +#if defined(CONFIG_OF_FLATTREE)
>
> This would also change to require CONFIG_KEXEC_FILE.
>
>> +extern int delete_fdt_mem_rsv(void *fdt, unsigned long start,
>> + unsigned long size);
>> +#endif /* CONFIG_OF_FLATTREE */
>> +
>> #endif /* !defined(__ASSEBMLY__) */
>>
>> #endif /* LINUX_KEXEC_H */
>
>
On 12/6/20 5:50 PM, Lakshmi Ramasubramanian wrote:
Hi Thiago,
> On 12/4/20 6:22 PM, Thiago Jung Bauermann wrote
>>
>> Hello Lakshmi,
>>
>> Lakshmi Ramasubramanian <[email protected]> writes:
>>
>>> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
>>> the given starting address and size, from the device tree blob, and
>>> removes the entry from the device tree blob. This function is called
>>> to free the resources reserved for the buffer used for carrying forward
>>> the IMA measurement logs on kexec. This function does not have
>>> architecture specific code, but is currently limited to powerpc.
>>>
>>> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
>>
>> s/kexec_fdt.c/kexec.c/
>
> Missed that in the patch description. Will fix it. Thanks.
>
>>> accessible for other architectures as well.
>>>
>>> Co-developed-by: Prakhar Srivastava <[email protected]>
>>> Signed-off-by: Prakhar Srivastava <[email protected]>
>>> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
>>> ---
>>> arch/powerpc/include/asm/kexec.h | 1 -
>>> arch/powerpc/kexec/file_load.c | 32 -----------------
>>> drivers/of/Makefile | 1 +
>>> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
>>> include/linux/kexec.h | 5 +++
>>> 5 files changed, 67 insertions(+), 33 deletions(-)
>>> create mode 100644 drivers/of/kexec.c
>>>
>>> diff --git a/arch/powerpc/include/asm/kexec.h
>>> b/arch/powerpc/include/asm/kexec.h
>>> index 55d6ede30c19..7c223031ecdd 100644
>>> --- a/arch/powerpc/include/asm/kexec.h
>>> +++ b/arch/powerpc/include/asm/kexec.h
>>> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const
>>> void *slave_code,
>>> int setup_new_fdt(const struct kimage *image, void *fdt,
>>> unsigned long initrd_load_addr, unsigned long initrd_len,
>>> const char *cmdline);
>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long
>>> size);
>>> #ifdef CONFIG_PPC64
>>> struct kexec_buf;
>>> diff --git a/arch/powerpc/kexec/file_load.c
>>> b/arch/powerpc/kexec/file_load.c
>>> index 9a232bc36c8f..9efc98b1e2ae 100644
>>> --- a/arch/powerpc/kexec/file_load.c
>>> +++ b/arch/powerpc/kexec/file_load.c
>>> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const
>>> void *slave_code,
>>> return 0;
>>> }
>>> -/**
>>> - * delete_fdt_mem_rsv - delete memory reservation with given address
>>> and size
>>> - *
>>> - * Return: 0 on success, or negative errno on error.
>>> - */
>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long
>>> size)
>>> -{
>>> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
>>> -
>>> - for (i = 0; i < num_rsvs; i++) {
>>> - uint64_t rsv_start, rsv_size;
>>> -
>>> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>>> - if (ret) {
>>> - pr_err("Malformed device tree.\n");
>>> - return -EINVAL;
>>> - }
>>> -
>>> - if (rsv_start == start && rsv_size == size) {
>>> - ret = fdt_del_mem_rsv(fdt, i);
>>> - if (ret) {
>>> - pr_err("Error deleting device tree reservation.\n");
>>> - return -EINVAL;
>>> - }
>>> -
>>> - return 0;
>>> - }
>>> - }
>>> -
>>> - return -ENOENT;
>>> -}
>>> -
>>> /*
>>> * setup_new_fdt - modify /chosen and memory reservation for the
>>> next kernel
>>> * @image: kexec image being loaded.
>>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>>> index 6e1e5212f058..77d24712c0c8 100644
>>> --- a/drivers/of/Makefile
>>> +++ b/drivers/of/Makefile
>>> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>>> obj-$(CONFIG_OF_RESOLVE) += resolver.o
>>> obj-$(CONFIG_OF_OVERLAY) += overlay.o
>>> obj-$(CONFIG_OF_NUMA) += of_numa.o
>>> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
>>
>> Isn't this too broad? kexec.o will only be useful to kernel configs
>> which enable CONFIG_KEXEC_FILE, so perhaps do:
>>
>> ifdef CONFIG_OF_FLATTREE
>> ifdef CONFIG_KEXEC_FILE
>> obj-y += kexec.o
>> endif
>> endif
>>
>> What do you think?
>
> Per Rob's feedback on v9 patch set, I have moved all the architecture
> independent ima kexec functions to a single file "drivers/of/kexec.c"
>
> Since these functions are enabled on different kernel CONFIGs, I have
> used IS_ENABLED(CONFIG_XYZ) macro instead of "#ifdef" in the C file to
> conditionally compile.
Per Rob's feedback on the v9 patch, I'll keep the ima kexec functions in
a single file (in "drivers/of/kexec.c") and use IS_ENABLED() macro to
handle the function calls.
I'll make the other changes you'd suggested on v10 patches and will post
v11 patch set shortly.
thanks,
-lakshmi
>
>>
>>> obj-$(CONFIG_OF_UNITTEST) += unittest-data/
>>> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
>>> new file mode 100644
>>> index 000000000000..b7d59105fcb8
>>> --- /dev/null
>>> +++ b/drivers/of/kexec.c
>>> @@ -0,0 +1,61 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +/*
>>> + * Copyright (C) 2020 Microsoft Corporation
>>> + *
>>> + * Author: Lakshmi Ramasubramanian ([email protected])
>>> + *
>>> + * File: kexec.c
>>> + * Defines kexec related functions.
>>> + */
>>> +
>>> +#define pr_fmt(fmt) "OF: kexec: " fmt
>>> +
>>> +#include <linux/kernel.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/memblock.h>
>>> +#include <linux/kexec.h>
>>> +#include <linux/of.h>
>>> +#include <linux/of_fdt.h>
>>> +#include <linux/libfdt.h>
>>> +
>>> +/**
>>> + * delete_fdt_mem_rsv - delete memory reservation with given address
>>> and size
>>> + *
>>> + * @fdt: Flattened Device Tree to update
>>> + * @start: Starting address of the reservation to delete
>>> + * @size: Size of the reservation to delete
>>> + *
>>> + * Return: 0 on success, or negative errno on error.
>>> + */
>>> +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long
>>> size)
>>> +{
>>> + int i, ret, num_rsvs;
>>> +
>>> + if (!IS_ENABLED(CONFIG_KEXEC_FILE))
>>> + return 0;
>>
>> If you agree with my suggestion, then this IS_ENABLED() wouldn't be
>> needed.
>>
>
> Please see my response above.
>
> If there is a way to keep all the ima kexec functions in a single file
> and yet not use "#ifdef" in C file to conditionally compile, please let
> me know. I'll update.
>
> thanks,
> -lakshmi
>
>>> +
>>> + num_rsvs = fdt_num_mem_rsv(fdt);
>>> + for (i = 0; i < num_rsvs; i++) {
>>> + uint64_t rsv_start, rsv_size;
>>> +
>>> + ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>>> + if (ret) {
>>> + pr_err("Malformed device tree.\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + if (rsv_start == start && rsv_size == size) {
>>> + ret = fdt_del_mem_rsv(fdt, i);
>>> + if (ret) {
>>> + pr_err("Error deleting device tree reservation.\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + pr_debug("Freed reserved memory at %lu of size %lu\n",
>>> + start, size);
>>> + return 0;
>>> + }
>>> + }
>>> +
>>> + return -ENOENT;
>>> +}
>>
>> The function code is unchanged apart from the addition of the
>> IS_ENABLED() and the pr_debug(), so that is good.
>>
>>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>>> index 9e93bef52968..d0234c4815da 100644
>>> --- a/include/linux/kexec.h
>>> +++ b/include/linux/kexec.h
>>> @@ -407,6 +407,11 @@ static inline int kexec_crash_loaded(void) {
>>> return 0; }
>>> #define kexec_in_progress false
>>> #endif /* CONFIG_KEXEC_CORE */
>>> +#if defined(CONFIG_OF_FLATTREE)
>>
>> This would also change to require CONFIG_KEXEC_FILE.
>>
>>> +extern int delete_fdt_mem_rsv(void *fdt, unsigned long start,
>>> + unsigned long size);
>>> +#endif /* CONFIG_OF_FLATTREE */
>>> +
>>> #endif /* !defined(__ASSEBMLY__) */
>>> #endif /* LINUX_KEXEC_H */
>>
>>
Hi Lakshmi,
Lakshmi Ramasubramanian <[email protected]> writes:
> On 12/6/20 5:50 PM, Lakshmi Ramasubramanian wrote:
>
> Hi Thiago,
>
>> On 12/4/20 6:22 PM, Thiago Jung Bauermann wrote
>>>
>>> Hello Lakshmi,
>>>
>>> Lakshmi Ramasubramanian <[email protected]> writes:
>>>
>>>> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
>>>> the given starting address and size, from the device tree blob, and
>>>> removes the entry from the device tree blob. This function is called
>>>> to free the resources reserved for the buffer used for carrying forward
>>>> the IMA measurement logs on kexec. This function does not have
>>>> architecture specific code, but is currently limited to powerpc.
>>>>
>>>> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
>>>
>>> s/kexec_fdt.c/kexec.c/
>> Missed that in the patch description. Will fix it. Thanks.
>>
>>>> accessible for other architectures as well.
>>>>
>>>> Co-developed-by: Prakhar Srivastava <[email protected]>
>>>> Signed-off-by: Prakhar Srivastava <[email protected]>
>>>> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
>>>> ---
>>>> arch/powerpc/include/asm/kexec.h | 1 -
>>>> arch/powerpc/kexec/file_load.c | 32 -----------------
>>>> drivers/of/Makefile | 1 +
>>>> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
>>>> include/linux/kexec.h | 5 +++
>>>> 5 files changed, 67 insertions(+), 33 deletions(-)
>>>> create mode 100644 drivers/of/kexec.c
>>>>
>>>> diff --git a/arch/powerpc/include/asm/kexec.h
>>>> b/arch/powerpc/include/asm/kexec.h
>>>> index 55d6ede30c19..7c223031ecdd 100644
>>>> --- a/arch/powerpc/include/asm/kexec.h
>>>> +++ b/arch/powerpc/include/asm/kexec.h
>>>> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void
>>>> *slave_code,
>>>> int setup_new_fdt(const struct kimage *image, void *fdt,
>>>> unsigned long initrd_load_addr, unsigned long initrd_len,
>>>> const char *cmdline);
>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
>>>> #ifdef CONFIG_PPC64
>>>> struct kexec_buf;
>>>> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
>>>> index 9a232bc36c8f..9efc98b1e2ae 100644
>>>> --- a/arch/powerpc/kexec/file_load.c
>>>> +++ b/arch/powerpc/kexec/file_load.c
>>>> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void
>>>> *slave_code,
>>>> return 0;
>>>> }
>>>> -/**
>>>> - * delete_fdt_mem_rsv - delete memory reservation with given address and
>>>> size
>>>> - *
>>>> - * Return: 0 on success, or negative errno on error.
>>>> - */
>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
>>>> -{
>>>> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
>>>> -
>>>> - for (i = 0; i < num_rsvs; i++) {
>>>> - uint64_t rsv_start, rsv_size;
>>>> -
>>>> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>>>> - if (ret) {
>>>> - pr_err("Malformed device tree.\n");
>>>> - return -EINVAL;
>>>> - }
>>>> -
>>>> - if (rsv_start == start && rsv_size == size) {
>>>> - ret = fdt_del_mem_rsv(fdt, i);
>>>> - if (ret) {
>>>> - pr_err("Error deleting device tree reservation.\n");
>>>> - return -EINVAL;
>>>> - }
>>>> -
>>>> - return 0;
>>>> - }
>>>> - }
>>>> -
>>>> - return -ENOENT;
>>>> -}
>>>> -
>>>> /*
>>>> * setup_new_fdt - modify /chosen and memory reservation for the next
>>>> kernel
>>>> * @image: kexec image being loaded.
>>>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>>>> index 6e1e5212f058..77d24712c0c8 100644
>>>> --- a/drivers/of/Makefile
>>>> +++ b/drivers/of/Makefile
>>>> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>>>> obj-$(CONFIG_OF_RESOLVE) += resolver.o
>>>> obj-$(CONFIG_OF_OVERLAY) += overlay.o
>>>> obj-$(CONFIG_OF_NUMA) += of_numa.o
>>>> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
>>>
>>> Isn't this too broad? kexec.o will only be useful to kernel configs
>>> which enable CONFIG_KEXEC_FILE, so perhaps do:
>>>
>>> ifdef CONFIG_OF_FLATTREE
>>> ifdef CONFIG_KEXEC_FILE
>>> obj-y += kexec.o
>>> endif
>>> endif
>>>
>>> What do you think?
>> Per Rob's feedback on v9 patch set, I have moved all the architecture
>> independent ima kexec functions to a single file "drivers/of/kexec.c"
>> Since these functions are enabled on different kernel CONFIGs, I have
>> used IS_ENABLED(CONFIG_XYZ) macro instead of "#ifdef" in the C file to
>> conditionally compile.
> Per Rob's feedback on the v9 patch, I'll keep the ima kexec functions in a
> single file (in "drivers/of/kexec.c") and use IS_ENABLED() macro to handle the
> function calls.
>
> I'll make the other changes you'd suggested on v10 patches and will post v11
> patch set shortly.
From a cursory look at the use of functions in this file, I got the
impression that there wouldn't be any reference to them in kernel
configs that didn't have CONFIG_KEXEC_FILE enabled, which is why I
suggested the change above. I think you can make it without any other
changes to the code.
I could be wrong though, and there could be some config which tried to
use some of these functions even when CONFIG_KEXEC_FILE is disabled. In
that case, the customary way to resolve it is to provide static inline
stub versions in a header file (not in a .c file) of just those
functions that are needed.
The reason why placing stub functions in header files is better is that
then the compiler has visibility of the dummy function when compiling
the source file which uses the function, and is able to eliminate the
dead code that arises from the function always returning one value.
Using IS_ENABLED() to do an early return as the first operation in the
function in a separate .c file means that the compiler doesn't know
anything and has to put a jump to the dummy function (only to
immediately return), and retain the code that deals with the possibility
of different values being returned.
It's not a big deal in this case because none of these functions is in a
hot path, but it does make the kernel text a tiny bit bigger than
necessary.
--
Thiago Jung Bauermann
IBM Linux Technology Center
On 12/11/20 10:19 AM, Thiago Jung Bauermann wrote:
>
> Hi Lakshmi,
>
> Lakshmi Ramasubramanian <[email protected]> writes:
>
>> On 12/6/20 5:50 PM, Lakshmi Ramasubramanian wrote:
>>
>> Hi Thiago,
>>
>>> On 12/4/20 6:22 PM, Thiago Jung Bauermann wrote
>>>>
>>>> Hello Lakshmi,
>>>>
>>>> Lakshmi Ramasubramanian <[email protected]> writes:
>>>>
>>>>> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
>>>>> the given starting address and size, from the device tree blob, and
>>>>> removes the entry from the device tree blob. This function is called
>>>>> to free the resources reserved for the buffer used for carrying forward
>>>>> the IMA measurement logs on kexec. This function does not have
>>>>> architecture specific code, but is currently limited to powerpc.
>>>>>
>>>>> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
>>>>
>>>> s/kexec_fdt.c/kexec.c/
>>> Missed that in the patch description. Will fix it. Thanks.
>>>
>>>>> accessible for other architectures as well.
>>>>>
>>>>> Co-developed-by: Prakhar Srivastava <[email protected]>
>>>>> Signed-off-by: Prakhar Srivastava <[email protected]>
>>>>> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
>>>>> ---
>>>>> arch/powerpc/include/asm/kexec.h | 1 -
>>>>> arch/powerpc/kexec/file_load.c | 32 -----------------
>>>>> drivers/of/Makefile | 1 +
>>>>> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
>>>>> include/linux/kexec.h | 5 +++
>>>>> 5 files changed, 67 insertions(+), 33 deletions(-)
>>>>> create mode 100644 drivers/of/kexec.c
>>>>>
>>>>> diff --git a/arch/powerpc/include/asm/kexec.h
>>>>> b/arch/powerpc/include/asm/kexec.h
>>>>> index 55d6ede30c19..7c223031ecdd 100644
>>>>> --- a/arch/powerpc/include/asm/kexec.h
>>>>> +++ b/arch/powerpc/include/asm/kexec.h
>>>>> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void
>>>>> *slave_code,
>>>>> int setup_new_fdt(const struct kimage *image, void *fdt,
>>>>> unsigned long initrd_load_addr, unsigned long initrd_len,
>>>>> const char *cmdline);
>>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
>>>>> #ifdef CONFIG_PPC64
>>>>> struct kexec_buf;
>>>>> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
>>>>> index 9a232bc36c8f..9efc98b1e2ae 100644
>>>>> --- a/arch/powerpc/kexec/file_load.c
>>>>> +++ b/arch/powerpc/kexec/file_load.c
>>>>> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void
>>>>> *slave_code,
>>>>> return 0;
>>>>> }
>>>>> -/**
>>>>> - * delete_fdt_mem_rsv - delete memory reservation with given address and
>>>>> size
>>>>> - *
>>>>> - * Return: 0 on success, or negative errno on error.
>>>>> - */
>>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
>>>>> -{
>>>>> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
>>>>> -
>>>>> - for (i = 0; i < num_rsvs; i++) {
>>>>> - uint64_t rsv_start, rsv_size;
>>>>> -
>>>>> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>>>>> - if (ret) {
>>>>> - pr_err("Malformed device tree.\n");
>>>>> - return -EINVAL;
>>>>> - }
>>>>> -
>>>>> - if (rsv_start == start && rsv_size == size) {
>>>>> - ret = fdt_del_mem_rsv(fdt, i);
>>>>> - if (ret) {
>>>>> - pr_err("Error deleting device tree reservation.\n");
>>>>> - return -EINVAL;
>>>>> - }
>>>>> -
>>>>> - return 0;
>>>>> - }
>>>>> - }
>>>>> -
>>>>> - return -ENOENT;
>>>>> -}
>>>>> -
>>>>> /*
>>>>> * setup_new_fdt - modify /chosen and memory reservation for the next
>>>>> kernel
>>>>> * @image: kexec image being loaded.
>>>>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>>>>> index 6e1e5212f058..77d24712c0c8 100644
>>>>> --- a/drivers/of/Makefile
>>>>> +++ b/drivers/of/Makefile
>>>>> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>>>>> obj-$(CONFIG_OF_RESOLVE) += resolver.o
>>>>> obj-$(CONFIG_OF_OVERLAY) += overlay.o
>>>>> obj-$(CONFIG_OF_NUMA) += of_numa.o
>>>>> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
>>>>
>>>> Isn't this too broad? kexec.o will only be useful to kernel configs
>>>> which enable CONFIG_KEXEC_FILE, so perhaps do:
>>>>
>>>> ifdef CONFIG_OF_FLATTREE
>>>> ifdef CONFIG_KEXEC_FILE
>>>> obj-y += kexec.o
>>>> endif
>>>> endif
>>>>
>>>> What do you think?
>>> Per Rob's feedback on v9 patch set, I have moved all the architecture
>>> independent ima kexec functions to a single file "drivers/of/kexec.c"
>>> Since these functions are enabled on different kernel CONFIGs, I have
>>> used IS_ENABLED(CONFIG_XYZ) macro instead of "#ifdef" in the C file to
>>> conditionally compile.
>> Per Rob's feedback on the v9 patch, I'll keep the ima kexec functions in a
>> single file (in "drivers/of/kexec.c") and use IS_ENABLED() macro to handle the
>> function calls.
>>
>> I'll make the other changes you'd suggested on v10 patches and will post v11
>> patch set shortly.
>
>>From a cursory look at the use of functions in this file, I got the
> impression that there wouldn't be any reference to them in kernel
> configs that didn't have CONFIG_KEXEC_FILE enabled, which is why I
> suggested the change above. I think you can make it without any other
> changes to the code.
>
> I could be wrong though, and there could be some config which tried to
> use some of these functions even when CONFIG_KEXEC_FILE is disabled. In
> that case, the customary way to resolve it is to provide static inline
> stub versions in a header file (not in a .c file) of just those
> functions that are needed.
>
> The reason why placing stub functions in header files is better is that
> then the compiler has visibility of the dummy function when compiling
> the source file which uses the function, and is able to eliminate the
> dead code that arises from the function always returning one value.
I agree with you Thiago.
Is there a way to keep all the relevant functions in a single C file,
not use "#ifdef" in C file, and follow the coding pattern you've
described above (i mean, "defining a stub function in a header file when
the config conditions are not met")?
>
> Using IS_ENABLED() to do an early return as the first operation in the
> function in a separate .c file means that the compiler doesn't know
> anything and has to put a jump to the dummy function (only to
> immediately return), and retain the code that deals with the possibility
> of different values being returned.
>
> It's not a big deal in this case because none of these functions is in a
> hot path, but it does make the kernel text a tiny bit bigger than
> necessary.
>
I agree.
thanks,
-lakshmi
Lakshmi Ramasubramanian <[email protected]> writes:
> On 12/11/20 10:19 AM, Thiago Jung Bauermann wrote:
>> Hi Lakshmi,
>> Lakshmi Ramasubramanian <[email protected]> writes:
>>
>>> On 12/6/20 5:50 PM, Lakshmi Ramasubramanian wrote:
>>>
>>> Hi Thiago,
>>>
>>>> On 12/4/20 6:22 PM, Thiago Jung Bauermann wrote
>>>>>
>>>>> Hello Lakshmi,
>>>>>
>>>>> Lakshmi Ramasubramanian <[email protected]> writes:
>>>>>
>>>>>> delete_fdt_mem_rsv() retrieves the memory reserve map entry, for
>>>>>> the given starting address and size, from the device tree blob, and
>>>>>> removes the entry from the device tree blob. This function is called
>>>>>> to free the resources reserved for the buffer used for carrying forward
>>>>>> the IMA measurement logs on kexec. This function does not have
>>>>>> architecture specific code, but is currently limited to powerpc.
>>>>>>
>>>>>> Move delete_fdt_mem_rsv() to "drivers/of/kexec_fdt.c" so that it is
>>>>>
>>>>> s/kexec_fdt.c/kexec.c/
>>>> Missed that in the patch description. Will fix it. Thanks.
>>>>
>>>>>> accessible for other architectures as well.
>>>>>>
>>>>>> Co-developed-by: Prakhar Srivastava <[email protected]>
>>>>>> Signed-off-by: Prakhar Srivastava <[email protected]>
>>>>>> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
>>>>>> ---
>>>>>> arch/powerpc/include/asm/kexec.h | 1 -
>>>>>> arch/powerpc/kexec/file_load.c | 32 -----------------
>>>>>> drivers/of/Makefile | 1 +
>>>>>> drivers/of/kexec.c | 61 ++++++++++++++++++++++++++++++++
>>>>>> include/linux/kexec.h | 5 +++
>>>>>> 5 files changed, 67 insertions(+), 33 deletions(-)
>>>>>> create mode 100644 drivers/of/kexec.c
>>>>>>
>>>>>> diff --git a/arch/powerpc/include/asm/kexec.h
>>>>>> b/arch/powerpc/include/asm/kexec.h
>>>>>> index 55d6ede30c19..7c223031ecdd 100644
>>>>>> --- a/arch/powerpc/include/asm/kexec.h
>>>>>> +++ b/arch/powerpc/include/asm/kexec.h
>>>>>> @@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void
>>>>>> *slave_code,
>>>>>> int setup_new_fdt(const struct kimage *image, void *fdt,
>>>>>> unsigned long initrd_load_addr, unsigned long initrd_len,
>>>>>> const char *cmdline);
>>>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
>>>>>> #ifdef CONFIG_PPC64
>>>>>> struct kexec_buf;
>>>>>> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
>>>>>> index 9a232bc36c8f..9efc98b1e2ae 100644
>>>>>> --- a/arch/powerpc/kexec/file_load.c
>>>>>> +++ b/arch/powerpc/kexec/file_load.c
>>>>>> @@ -109,38 +109,6 @@ int setup_purgatory(struct kimage *image, const void
>>>>>> *slave_code,
>>>>>> return 0;
>>>>>> }
>>>>>> -/**
>>>>>> - * delete_fdt_mem_rsv - delete memory reservation with given address and
>>>>>> size
>>>>>> - *
>>>>>> - * Return: 0 on success, or negative errno on error.
>>>>>> - */
>>>>>> -int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
>>>>>> -{
>>>>>> - int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
>>>>>> -
>>>>>> - for (i = 0; i < num_rsvs; i++) {
>>>>>> - uint64_t rsv_start, rsv_size;
>>>>>> -
>>>>>> - ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
>>>>>> - if (ret) {
>>>>>> - pr_err("Malformed device tree.\n");
>>>>>> - return -EINVAL;
>>>>>> - }
>>>>>> -
>>>>>> - if (rsv_start == start && rsv_size == size) {
>>>>>> - ret = fdt_del_mem_rsv(fdt, i);
>>>>>> - if (ret) {
>>>>>> - pr_err("Error deleting device tree reservation.\n");
>>>>>> - return -EINVAL;
>>>>>> - }
>>>>>> -
>>>>>> - return 0;
>>>>>> - }
>>>>>> - }
>>>>>> -
>>>>>> - return -ENOENT;
>>>>>> -}
>>>>>> -
>>>>>> /*
>>>>>> * setup_new_fdt - modify /chosen and memory reservation for the next
>>>>>> kernel
>>>>>> * @image: kexec image being loaded.
>>>>>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>>>>>> index 6e1e5212f058..77d24712c0c8 100644
>>>>>> --- a/drivers/of/Makefile
>>>>>> +++ b/drivers/of/Makefile
>>>>>> @@ -13,5 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>>>>>> obj-$(CONFIG_OF_RESOLVE) += resolver.o
>>>>>> obj-$(CONFIG_OF_OVERLAY) += overlay.o
>>>>>> obj-$(CONFIG_OF_NUMA) += of_numa.o
>>>>>> +obj-$(CONFIG_OF_FLATTREE) += kexec.o
>>>>>
>>>>> Isn't this too broad? kexec.o will only be useful to kernel configs
>>>>> which enable CONFIG_KEXEC_FILE, so perhaps do:
>>>>>
>>>>> ifdef CONFIG_OF_FLATTREE
>>>>> ifdef CONFIG_KEXEC_FILE
>>>>> obj-y += kexec.o
>>>>> endif
>>>>> endif
>>>>>
>>>>> What do you think?
>>>> Per Rob's feedback on v9 patch set, I have moved all the architecture
>>>> independent ima kexec functions to a single file "drivers/of/kexec.c"
>>>> Since these functions are enabled on different kernel CONFIGs, I have
>>>> used IS_ENABLED(CONFIG_XYZ) macro instead of "#ifdef" in the C file to
>>>> conditionally compile.
>>> Per Rob's feedback on the v9 patch, I'll keep the ima kexec functions in a
>>> single file (in "drivers/of/kexec.c") and use IS_ENABLED() macro to handle the
>>> function calls.
>>>
>>> I'll make the other changes you'd suggested on v10 patches and will post v11
>>> patch set shortly.
>>
>>>From a cursory look at the use of functions in this file, I got the
>> impression that there wouldn't be any reference to them in kernel
>> configs that didn't have CONFIG_KEXEC_FILE enabled, which is why I
>> suggested the change above. I think you can make it without any other
>> changes to the code.
>> I could be wrong though, and there could be some config which tried to
>> use some of these functions even when CONFIG_KEXEC_FILE is disabled. In
>> that case, the customary way to resolve it is to provide static inline
>> stub versions in a header file (not in a .c file) of just those
>> functions that are needed.
>> The reason why placing stub functions in header files is better is that
>> then the compiler has visibility of the dummy function when compiling
>> the source file which uses the function, and is able to eliminate the
>> dead code that arises from the function always returning one value.
>
> I agree with you Thiago.
>
> Is there a way to keep all the relevant functions in a single C file, not use
> "#ifdef" in C file, and follow the coding pattern you've described above (i
> mean, "defining a stub function in a header file when the config conditions are
> not met")?
Like I said above, my impression is that you don't need any ifdefs since
my understanding is that all funcitons in the C file are only used when
CONFIG_KEXEC_FILE is set. Do you anticipate (or have found) problems
with that?
--
Thiago Jung Bauermann
IBM Linux Technology Center