On 09/13/18 18:26, Frank Rowand wrote: > I was re-reading this while answering a later email in the thread. After reading > other patches in the series that were not sent to me, I have a better understanding > of the intent behind this patch, and some changes to my previous reply. > > The intent of the helper functions is related to properties whose values are > tuples of the same format as the "reg" property of the "/memory" nodes. For > example, the "linux,usable-memory-range" and "linux,elfcoredhr" properties of > the "/chosen" node. > > The patch header and the function names should be updated to reflect this intent. > This means most or all of my previous suggested function name changes are no longer > useful. > > Please add devicetree@xxxxxxxxxxxxxxx to the next version of this patch and to > the patches that use the functions in this patch. > > > On 09/07/18 12:53, Frank Rowand wrote: >> On 09/07/18 01:00, AKASHI Takahiro wrote: >>> These functions will be used later to handle kexec-specific properties >>> in arm64's kexec_file implementation. >>> >>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> >>> Cc: Rob Herring <robh+dt@xxxxxxxxxx> >>> Cc: Frank Rowand <frowand.list@xxxxxxxxx> >>> --- >>> drivers/of/fdt.c | 62 ++++++++++++++++++++++++++++++++++++++++-- >>> include/linux/of_fdt.h | 10 +++++-- >>> 2 files changed, 68 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >>> index 800ad252cf9c..dc960cea1355 100644 >>> --- a/drivers/of/fdt.c >>> +++ b/drivers/of/fdt.c >>> @@ -25,6 +25,7 @@ >>> #include <linux/debugfs.h> >>> #include <linux/serial_core.h> >>> #include <linux/sysfs.h> >>> +#include <linux/types.h> >>> >>> #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ >>> #include <asm/page.h> >>> @@ -537,8 +538,8 @@ void *of_fdt_unflatten_tree(const unsigned long *blob, >>> EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); >>> >>> /* Everything below here references initial_boot_params directly. */ >>> -int __initdata dt_root_addr_cells; >>> -int __initdata dt_root_size_cells; >>> +int dt_root_addr_cells; >>> +int dt_root_size_cells; >>> >>> void *initial_boot_params; >>> >>> @@ -1323,3 +1324,60 @@ late_initcall(of_fdt_raw_init); >>> #endif >>> >>> #endif /* CONFIG_OF_EARLY_FLATTREE */ >>> + > > Global comment: this code should not be using the variables > dt_root_addr_cells and dt_root_size_cells. These variables are > __initdata. > > The code that is using these helpers is acting upon a specific FDT > (copied from initial_boot_params). This code should be getting the > values of the root node's "#address-cells" and "#size-cells" from > the FDT. There will be new functions available soon to return the values of a node's "#address-cells" and "#size-cells" from an fdt. They are fdt_address_cells() and fdt_size_cells(). Rob submitted the patch to add them yesterday in "[PATCH 3/3] scripts/dtc: Update to upstream version v1.4.7-14-gc86da84d30e4" [1] [1] https://lkml.kernel.org/r/<20180913202828.15372-3-robh@xxxxxxxxxx> -Frank > > >> Please add comment: >> >> /* helper functions for arm64 kexec */ >> >> >>> +bool of_fdt_cells_size_fitted(u64 base, u64 size) >> >> Please rename as of_fdt_range_valid() > > I'm not entirely sure of what the caller in 12/16 is trying to ensure > with this function. > > (1) At the minimum (and what the implementation in of_fdt_cells_size_fitted() > does) is make sure that an address and size tuple are consistent with > the root properties "#address-cells" and "#size-cells". > > The caller in 12/16 is using this check to validate values for the > properties "linux,elfcorehdr" and "linux,usable-memory-range". > > (2) A more complete check _might_ be to ensure that the values also > specify memory that is available to the kernel. This memory is described > by the "reg" property of one or more "/memory" nodes. > > This second check is probably what is actually desired. > > One possible issue to note is that the binding for "linux,usable-memory-range" > suggests that available memory could be described by an EFI memory map. > I am not familiar with how or when an EFI memory map might exist instead > of the "/memory" nodes. > > >>> +{ >>> + /* if *_cells >= 2, cells can hold 64-bit values anyway */ >>> + if ((dt_root_addr_cells == 1) && (base > U32_MAX)) >>> + return false; >>> + >>> + if ((dt_root_size_cells == 1) && (size > U32_MAX)) >>> + return false; >> >> Should also check that base + size does not wrap around. >> >> >>> + >>> + return true; >>> +} >>> + >>> +size_t of_fdt_reg_cells_size(void) >> >> Please rename as of_fdt_root_range_size() > > Even better would be to remove this function and replace the one place > that it is called from with the one line of code in this function. > > -Frank > > >>> +{ >>> + return (dt_root_addr_cells + dt_root_size_cells) * sizeof(u32); >>> +} >>> + >>> +#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1)) >>> +#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE)) >>> + >>> +int fdt_prop_len(const char *prop_name, int len) >> >> Please rename as fdt_len_added_prop() >> >> >>> +{ >>> + return (strlen(prop_name) + 1) + >>> + sizeof(struct fdt_property) + >>> + FDT_TAGALIGN(len); >>> +} >>> + >> >> Please add comment, something like: >> >> /* cells must be 1 or 2 */ >> >> >>> +static void fill_property(void *buf, u64 val64, int cells) >> >> Please rename as cpu64_to_fdt_cells() >> >> Thanks, >> >> Frank >> >>> +{ >>> + __be32 val32; >>> + >>> + while (cells) { >>> + val32 = cpu_to_fdt32((val64 >> (32 * (--cells))) & U32_MAX); >>> + memcpy(buf, &val32, sizeof(val32)); >>> + buf += sizeof(val32); >>> + } >>> +} >>> + >>> +int fdt_setprop_reg(void *fdt, int nodeoffset, const char *name, >>> + u64 addr, u64 size) >>> +{ >>> + char buf[sizeof(__be32) * 2 * 2]; >>> + /* assume dt_root_[addr|size]_cells <= 2 */ >>> + void *prop; >>> + size_t buf_size; >>> + >>> + buf_size = of_fdt_reg_cells_size(); >>> + prop = buf; >>> + >>> + fill_property(prop, addr, dt_root_addr_cells); >>> + prop += dt_root_addr_cells * sizeof(u32); >>> + >>> + fill_property(prop, size, dt_root_size_cells); >>> + >>> + return fdt_setprop(fdt, nodeoffset, name, buf, buf_size); >>> +} >>> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h >>> index b9cd9ebdf9b9..9615d6142578 100644 >>> --- a/include/linux/of_fdt.h >>> +++ b/include/linux/of_fdt.h >>> @@ -37,8 +37,8 @@ extern void *of_fdt_unflatten_tree(const unsigned long *blob, >>> struct device_node **mynodes); >>> >>> /* TBD: Temporary export of fdt globals - remove when code fully merged */ >>> -extern int __initdata dt_root_addr_cells; >>> -extern int __initdata dt_root_size_cells; >>> +extern int dt_root_addr_cells; >>> +extern int dt_root_size_cells; >>> extern void *initial_boot_params; >>> >>> extern char __dtb_start[]; >>> @@ -108,5 +108,11 @@ static inline void unflatten_device_tree(void) {} >>> static inline void unflatten_and_copy_device_tree(void) {} >>> #endif /* CONFIG_OF_EARLY_FLATTREE */ >>> >>> +bool of_fdt_cells_size_fitted(u64 base, u64 size); >>> +size_t of_fdt_reg_cells_size(void); >>> +int fdt_prop_len(const char *prop_name, int len); >>> +int fdt_setprop_reg(void *fdt, int nodeoffset, const char *name, >>> + u64 addr, u64 size); >>> + >>> #endif /* __ASSEMBLY__ */ >>> #endif /* _LINUX_OF_FDT_H */ >>> >> >> > > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
