Currently armv7 kernels expect to be loaded at the bottom of physical
ram. The diff below removes this restriction.
This is important for two reasons:
1. On some SoCs physical memory starts at address 0. However, the
u-boot EFI interface has a nasty bug where allocating memory at
address 0 always succeeds. Even if there is no memory at that
address! Therefore BOOTARM.EFI starts looking for available memory
to load the kernel at address 0x10000000.
2. There is not guarantee that we can always load the kernel at the
bottom of physical memory as that memory might be in use by the
firmware.
The diff passes the physical address at which the kernel has been
loaded in arg0, which is currently unused. The assembly code that
forms the entry point of the kernel already calculated this address so
passing it is trivial. If we weren't loaded at the bottom of physical
memory, we will make the memory pages before the kernel available to
uvm such that we don't lose any memory.
ok (after unlock)?
Index: arch/armv7/armv7/armv7_machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/armv7/armv7/armv7_machdep.c,v
retrieving revision 1.31
diff -u -p -r1.31 armv7_machdep.c
--- arch/armv7/armv7/armv7_machdep.c 14 Jun 2016 10:03:51 -0000 1.31
+++ arch/armv7/armv7/armv7_machdep.c 21 Jul 2016 20:58:08 -0000
@@ -389,6 +389,7 @@ initarm(void *arg0, void *arg1, void *ar
u_int l1pagetable;
pv_addr_t kernel_l1pt;
pv_addr_t fdt;
+ paddr_t loadaddr;
paddr_t memstart;
psize_t memsize;
void *config;
@@ -399,6 +400,7 @@ initarm(void *arg0, void *arg1, void *ar
int (*map_func_save)(void *, bus_addr_t, bus_size_t, int,
bus_space_handle_t *);
+ loadaddr = (paddr_t)arg0;
board_id = (uint32_t)arg1;
/*
* u-boot has decided the top four bits are
@@ -514,7 +516,7 @@ initarm(void *arg0, void *arg1, void *ar
boothowto |= RB_DFLTROOT;
#endif /* RAMDISK_HOOKS */
- physical_freestart = (((unsigned long)esym - KERNEL_TEXT_BASE +0xfff) &
~0xfff) + memstart;
+ physical_freestart = (((unsigned long)esym - KERNEL_TEXT_BASE +0xfff) &
~0xfff) + loadaddr;
physical_freeend = MIN((uint64_t)memstart+memsize, (paddr_t)-PAGE_SIZE);
physmem = (physical_end - physical_start) / PAGE_SIZE;
@@ -557,7 +559,7 @@ initarm(void *arg0, void *arg1, void *ar
/* Define a macro to simplify memory allocation */
#define valloc_pages(var, np) \
alloc_pages((var).pv_pa, (np)); \
- (var).pv_va = KERNEL_BASE + (var).pv_pa - physical_start;
+ (var).pv_va = KERNEL_BASE + (var).pv_pa - loadaddr;
#define alloc_pages(var, np) \
(var) = physical_freestart; \
@@ -677,10 +679,10 @@ initarm(void *arg0, void *arg1, void *ar
logical = 0x00000000; /* offset of kernel in RAM */
logical += pmap_map_chunk(l1pagetable, KERNEL_BASE + logical,
- physical_start + logical, textsize,
+ loadaddr + logical, textsize,
PROT_READ | PROT_WRITE | PROT_EXEC, PTE_CACHE);
logical += pmap_map_chunk(l1pagetable, KERNEL_BASE + logical,
- physical_start + logical, totalsize - textsize,
+ loadaddr + logical, totalsize - textsize,
PROT_READ | PROT_WRITE, PTE_CACHE);
}
@@ -798,6 +800,12 @@ initarm(void *arg0, void *arg1, void *ar
atop(physical_freestart), atop(physical_freeend), 0);
physsegs = MIN(bootconfig.dramblocks, VM_PHYSSEG_MAX);
+
+ if (physical_start < loadaddr) {
+ uvm_page_physload(atop(physical_start), atop(loadaddr),
+ atop(physical_start), atop(loadaddr), 0);
+ physsegs--;
+ }
for (i = 1; i < physsegs; i++) {
paddr_t dramstart = bootconfig.dram[i].address;
Index: arch/armv7/armv7/armv7_start.S
===================================================================
RCS file: /cvs/src/sys/arch/armv7/armv7/armv7_start.S,v
retrieving revision 1.6
diff -u -p -r1.6 armv7_start.S
--- arch/armv7/armv7/armv7_start.S 25 Apr 2016 04:46:57 -0000 1.6
+++ arch/armv7/armv7/armv7_start.S 21 Jul 2016 20:58:08 -0000
@@ -161,7 +161,7 @@ _C_LABEL(bootstrap_start):
CPWAIT(r0)
/* Restore U-Boot arguments */
- mov r0, r6
+ mov r0, r9
mov r1, r7
mov r2, r8
