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lib: Fix CPU capabilities detection function

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On some platforms, misa may not be implemented. On such a platform,
reading misa will get 0. At this time, platform is required to
implement a non-standard function to detect the CPU's capabilities.
Therefore, this modification add interfaces for non-standard function.

The MXL field of misa is always at the highest two bits, whether it
is a 32-bit 64-bit or a 128-bit machine. Therefore, this modification
fixes the use of a fixed offset to detect the machine length.

Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Xiang Wang
2019-11-26 16:06:29 +05:30
committed by Anup Patel
parent 75f903dd78
commit c96cc03fcc
4 changed files with 89 additions and 12 deletions
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40
include/sbi/sbi_platform.h
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@@ -76,6 +76,16 @@ struct sbi_platform_operations {
/** Platform final initialization */
int (*final_init)(bool cold_boot);
/** For platforms that do not implement misa, non-standard
* methods are needed to determine cpu extension.
*/
int (*misa_check_extension)(char ext);
/** For platforms that do not implement misa, non-standard
* methods are needed to get MXL field of misa.
*/
int (*misa_get_xlen)(void);
/** Get number of PMP regions for given HART */
u32 (*pmp_region_count)(u32 hartid);
/**
@@ -291,6 +301,36 @@ static inline int sbi_platform_final_init(const struct sbi_platform *plat,
return 0;
}
/**
* Check CPU extension in MISA
*
* @param plat pointer to struct sbi_platform
* @param ext shorthand letter for CPU extensions
*
* @return zero for not-supported and non-zero for supported
*/
static inline int sbi_platform_misa_extension(const struct sbi_platform *plat,
char ext)
{
if (plat && sbi_platform_ops(plat)->misa_check_extension)
return sbi_platform_ops(plat)->misa_check_extension(ext);
return 0;
}
/**
* Get MXL field of MISA
*
* @param plat pointer to struct sbi_platform
*
* @return 1/2/3 on success and error code on failure
*/
static inline int sbi_platform_misa_xlen(const struct sbi_platform *plat)
{
if (plat && sbi_platform_ops(plat)->misa_get_xlen)
return sbi_platform_ops(plat)->misa_get_xlen();
return -1;
}
/**
* Get the number of PMP regions of a HART
*