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authorAnup Patel <anup.patel@wdc.com>2019-11-06 16:24:35 +0530
committerAnup Patel <anup@brainfault.org>2019-11-15 17:41:18 +0530
commit7a13beb213266cbf6f15ddbbef5bfca274086bd3 (patch)
tree31feb9270d13674ef8134618729a06ea269d46eb
parent18897aaf5d0382017c05a5690d0bc8e0d044270f (diff)
firmware: Add preferred boot HART field in struct fw_dynamic_info
It has been reported that link address range of previous booting stage (such as U-Boot SPL) can overlap the link address rage of FW_DYNAMIC. This means self-relocation in FW_DYNAMIC can potentially corrupt previous booting stage if any of the secondary HART enter FW_DYNAMIC before primary HART. To tackle this, we add preferred boot HART field (i.e boot_hart) in struct fw_dyanmic_info. We use this field to force secondary HARTs into relocation wait loop till preferred/primary boot HART enters FW_DYNAMIC completes self-relocation. If preferred boot HART is not available then we fall back to relocation lottery approach. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Atish Patra <atish.patra@wdc.com>
Diffstat
-rw-r--r--firmware/fw_base.S10
-rw-r--r--firmware/fw_dynamic.S42
-rw-r--r--firmware/fw_jump.S13
-rw-r--r--firmware/fw_payload.S13
-rw-r--r--include/sbi/fw_dynamic.h26
5 files changed, 100 insertions, 4 deletions
diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index 375c158..0797cc0 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -46,6 +46,16 @@
.globl _start
.globl _start_warm
_start:
+ /* Find preferred boot HART id */
+ MOV_3R s0, a0, s1, a1, s2, a2
+ call fw_boot_hart
+ add a6, a0, zero
+ MOV_3R a0, s0, a1, s1, a2, s2
+ li a7, -1
+ beq a6, a7, _try_lottery
+ /* Jump to relocation wait loop if we are not boot hart */
+ bne a0, a6, _wait_relocate_copy_done
+_try_lottery:
/* Jump to relocation wait loop if we don't get relocation lottery */
la a6, _relocate_lottery
li a7, 1
diff --git a/firmware/fw_dynamic.S b/firmware/fw_dynamic.S
index cf97b60..ba9394d 100644
--- a/firmware/fw_dynamic.S
+++ b/firmware/fw_dynamic.S
@@ -19,6 +19,32 @@ _bad_dynamic_info:
.align 3
.section .entry, "ax", %progbits
+ .global fw_boot_hart
+ /*
+ * This function is called very early even before
+ * fw_save_info() is called.
+ * We can only use a0, a1, and a2 registers here.
+ * The boot HART id should be returned in 'a0'.
+ */
+fw_boot_hart:
+ /* Sanity checks */
+ li a1, FW_DYNAMIC_INFO_MAGIC_VALUE
+ REG_L a0, FW_DYNAMIC_INFO_MAGIC_OFFSET(a2)
+ bne a0, a1, _bad_dynamic_info
+ li a1, FW_DYNAMIC_INFO_VERSION_MAX
+ REG_L a0, FW_DYNAMIC_INFO_VERSION_OFFSET(a2)
+ bgt a0, a1, _bad_dynamic_info
+
+ /* Read boot HART id */
+ li a1, 0x2
+ blt a0, a1, 2f
+ REG_L a0, FW_DYNAMIC_INFO_BOOT_HART_OFFSET(a2)
+ ret
+2: li a0, -1
+ ret
+
+ .align 3
+ .section .entry, "ax", %progbits
.global fw_save_info
/*
* We can only use a0, a1, a2, a3, and a4 registers here.
@@ -27,14 +53,19 @@ _bad_dynamic_info:
* Nothing to be returned here.
*/
fw_save_info:
+ /* Save next arg1 in 'a1' */
la a4, _dynamic_next_arg1
REG_S a1, (a4)
+
+ /* Sanity checks */
li a4, FW_DYNAMIC_INFO_MAGIC_VALUE
REG_L a3, FW_DYNAMIC_INFO_MAGIC_OFFSET(a2)
bne a3, a4, _bad_dynamic_info
li a4, FW_DYNAMIC_INFO_VERSION_MAX
REG_L a3, FW_DYNAMIC_INFO_VERSION_OFFSET(a2)
bgt a3, a4, _bad_dynamic_info
+
+ /* Save version == 0x1 fields */
la a4, _dynamic_next_addr
REG_L a3, FW_DYNAMIC_INFO_NEXT_ADDR_OFFSET(a2)
REG_S a3, (a4)
@@ -44,6 +75,15 @@ fw_save_info:
la a4, _dynamic_options
REG_L a3, FW_DYNAMIC_INFO_OPTIONS_OFFSET(a2)
REG_S a3, (a4)
+
+ /* Save version == 0x2 fields */
+ li a4, 0x2
+ REG_L a3, FW_DYNAMIC_INFO_VERSION_OFFSET(a2)
+ blt a3, a4, 2f
+ la a4, _dynamic_boot_hart
+ REG_L a3, FW_DYNAMIC_INFO_BOOT_HART_OFFSET(a2)
+ REG_S a3, (a4)
+2:
ret
.align 3
@@ -116,3 +156,5 @@ _dynamic_next_mode:
RISCV_PTR PRV_S
_dynamic_options:
RISCV_PTR 0x0
+_dynamic_boot_hart:
+ RISCV_PTR -1
diff --git a/firmware/fw_jump.S b/firmware/fw_jump.S
index cdf1f41..84391c9 100644
--- a/firmware/fw_jump.S
+++ b/firmware/fw_jump.S
@@ -11,6 +11,19 @@
.align 3
.section .entry, "ax", %progbits
+ .global fw_boot_hart
+ /*
+ * This function is called very early even before
+ * fw_save_info() is called.
+ * We can only use a0, a1, and a2 registers here.
+ * The boot HART id should be returned in 'a0'.
+ */
+fw_boot_hart:
+ li a0, -1
+ ret
+
+ .align 3
+ .section .entry, "ax", %progbits
.global fw_save_info
/*
* We can only use a0, a1, a2, a3, and a4 registers here.
diff --git a/firmware/fw_payload.S b/firmware/fw_payload.S
index 01dce20..9f4e0ec 100644
--- a/firmware/fw_payload.S
+++ b/firmware/fw_payload.S
@@ -11,6 +11,19 @@
.align 3
.section .entry, "ax", %progbits
+ .global fw_boot_hart
+ /*
+ * This function is called very early even before
+ * fw_save_info() is called.
+ * We can only use a0, a1, and a2 registers here.
+ * The boot HART id should be returned in 'a0'.
+ */
+fw_boot_hart:
+ li a0, -1
+ ret
+
+ .align 3
+ .section .entry, "ax", %progbits
.global fw_save_info
/*
* We can only use a0, a1, a2, a3, and a4 registers here.
diff --git a/include/sbi/fw_dynamic.h b/include/sbi/fw_dynamic.h
index 695dc29..3c08831 100644
--- a/include/sbi/fw_dynamic.h
+++ b/include/sbi/fw_dynamic.h
@@ -18,18 +18,20 @@
#define FW_DYNAMIC_INFO_MAGIC_OFFSET (0 * __SIZEOF_POINTER__)
/** Offset of version member in fw_dynamic_info */
#define FW_DYNAMIC_INFO_VERSION_OFFSET (1 * __SIZEOF_POINTER__)
-/** Offset of next_addr member in fw_dynamic_info */
+/** Offset of next_addr member in fw_dynamic_info (version >= 1) */
#define FW_DYNAMIC_INFO_NEXT_ADDR_OFFSET (2 * __SIZEOF_POINTER__)
-/** Offset of next_mode member in fw_dynamic_info */
+/** Offset of next_mode member in fw_dynamic_info (version >= 1) */
#define FW_DYNAMIC_INFO_NEXT_MODE_OFFSET (3 * __SIZEOF_POINTER__)
-/** Offset of options member in fw_dynamic_info */
+/** Offset of options member in fw_dynamic_info (version >= 1) */
#define FW_DYNAMIC_INFO_OPTIONS_OFFSET (4 * __SIZEOF_POINTER__)
+/** Offset of boot_hart member in fw_dynamic_info (version >= 2) */
+#define FW_DYNAMIC_INFO_BOOT_HART_OFFSET (5 * __SIZEOF_POINTER__)
/** Expected value of info magic ('OSBI' ascii string in hex) */
#define FW_DYNAMIC_INFO_MAGIC_VALUE 0x4942534f
/** Maximum supported info version */
-#define FW_DYNAMIC_INFO_VERSION_MAX 0x1
+#define FW_DYNAMIC_INFO_VERSION_MAX 0x2
/** Possible next mode values */
#define FW_DYNAMIC_INFO_NEXT_MODE_U 0x0
@@ -54,6 +56,22 @@ struct fw_dynamic_info {
unsigned long next_mode;
/** Options for OpenSBI library */
unsigned long options;
+ /**
+ * Preferred boot HART id
+ *
+ * It is possible that the previous booting stage uses same link
+ * address as the FW_DYNAMIC firmware. In this case, the relocation
+ * lottery mechanism can potentially overwrite the previous booting
+ * stage while other HARTs are still running in the previous booting
+ * stage leading to boot-time crash. To avoid this boot-time crash,
+ * the previous booting stage can specify last HART that will jump
+ * to the FW_DYNAMIC firmware as the preferred boot HART.
+ *
+ * To avoid specifying a preferred boot HART, the previous booting
+ * stage can set it to -1UL which will force the FW_DYNAMIC firmware
+ * to use the relocation lottery mechanism.
+ */
+ unsigned long boot_hart;
} __packed;
#endif
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