On Mon, Jun 01, 2020 at 04:56:40PM +0200, Lukasz Stelmach wrote: > It was <2020-06-01 pon 15:46>, when Russell King - ARM Linux admin wrote: > > On Mon, Jun 01, 2020 at 04:27:50PM +0200, Łukasz Stelmach wrote: > >> Move the definition of malloc pool size of the decompressor to > >> a single place. This value will be exposed later for kexec_file loader. > >> > >> Signed-off-by: Łukasz Stelmach <[email protected]> > >> --- > >> arch/arm/boot/compressed/Makefile | 2 ++ > >> arch/arm/boot/compressed/head.S | 6 ++++-- > >> 2 files changed, 6 insertions(+), 2 deletions(-) > >> > >> diff --git a/arch/arm/boot/compressed/Makefile > >> b/arch/arm/boot/compressed/Makefile > >> index 9c11e7490292..b3594cd1588c 100644 > >> --- a/arch/arm/boot/compressed/Makefile > >> +++ b/arch/arm/boot/compressed/Makefile > >> @@ -125,6 +125,8 @@ KBSS_SZ = $(shell echo $$(($$($(NM) > >> $(obj)/../../../../vmlinux | \ > >> sed -n -e 's/^\([^ ]*\) [AB] __bss_start$$/-0x\1/p' \ > >> -e 's/^\([^ ]*\) [AB] __bss_stop$$/+0x\1/p') )) ) > >> LDFLAGS_vmlinux = --defsym _kernel_bss_size=$(KBSS_SZ) > >> +# malloc pool size > >> +LDFLAGS_vmlinux += --defsym _malloc_size=0x10000 > >> # Supply ZRELADDR to the decompressor via a linker symbol. > >> ifneq ($(CONFIG_AUTO_ZRELADDR),y) > >> LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR) > >> diff --git a/arch/arm/boot/compressed/head.S > >> b/arch/arm/boot/compressed/head.S > >> index e8e1c866e413..dcc1afa60fb9 100644 > >> --- a/arch/arm/boot/compressed/head.S > >> +++ b/arch/arm/boot/compressed/head.S > >> @@ -309,7 +309,8 @@ restart: adr r0, LC0 > >> #ifndef CONFIG_ZBOOT_ROM > >> /* malloc space is above the relocated stack (64k max) */ > >> add sp, sp, r0 > >> - add r10, sp, #0x10000 > >> + ldr r10, =_malloc_size > >> + add r10, r10, sp > > > > This says "locate _malloc_size in a literal pool somewhere, and load it > > using a PC-relative offset". Are you sure that the literal pool is > > sensibly located? > > > > Would it be better to use a definition for this? > > I've followed ZRELADDR way. I think both values should be handled the > same way (it makes it easier to comprehend IMHO). Is there any reason > not to? Should I change ZRELADDR for v2 too?
There's a good reason. ZRELADDR can be a constant that does not fit into the ARMs immediate constants (8 bits of significant data plus a multiple of a 2-bit shift), whereas the size of the malloc space is guaranteed to fit. So, ZRELADDR has to use a literal load. This doesn't. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up
