| Message ID | 20200601142754.26139-2-l.stelmach@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kexec_file_load() for arm | expand |
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 <l.stelmach@samsung.com> > --- > 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$$/+0x\1/p') )) ) > LDFLAGS_vmlinux = --defsym _kernel_bss_size=$(KBSS_SZ) > +# malloc pool size > +LDFLAGS_vmlinux += --defsym _malloc_size=0x10000 > # Supply ZRELADDR to the decompressor via a linker symbol. > ifneq ($(CONFIG_AUTO_ZRELADDR),y) > LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR) > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index e8e1c866e413..dcc1afa60fb9 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -309,7 +309,8 @@ restart: adr r0, LC0 > #ifndef CONFIG_ZBOOT_ROM > /* malloc space is above the relocated stack (64k max) */ > add sp, sp, r0 > - add r10, sp, #0x10000 > + ldr r10, =_malloc_size > + add r10, r10, sp This says "locate _malloc_size in a literal pool somewhere, and load it using a PC-relative offset". Are you sure that the literal pool is sensibly located? Would it be better to use a definition for this?
It was <2020-06-01 pon 15:46>, when Russell King - ARM Linux admin wrote: > On Mon, Jun 01, 2020 at 04:27:50PM +0200, Łukasz Stelmach wrote: >> Move the definition of malloc pool size of the decompressor to >> a single place. This value will be exposed later for kexec_file loader. >> >> Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com> >> --- >> arch/arm/boot/compressed/Makefile | 2 ++ >> arch/arm/boot/compressed/head.S | 6 ++++-- >> 2 files changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile >> index 9c11e7490292..b3594cd1588c 100644 >> --- a/arch/arm/boot/compressed/Makefile >> +++ b/arch/arm/boot/compressed/Makefile >> @@ -125,6 +125,8 @@ KBSS_SZ = $(shell echo $$(($$($(NM) $(obj)/../../../../vmlinux | \ >> sed -n -e 's/^\([^ ]*\) [AB] __bss_start$$/-0x\1/p' \ >> -e 's/^\([^ ]*\) [AB] __bss_stop$$/+0x\1/p') )) ) >> LDFLAGS_vmlinux = --defsym _kernel_bss_size=$(KBSS_SZ) >> +# malloc pool size >> +LDFLAGS_vmlinux += --defsym _malloc_size=0x10000 >> # Supply ZRELADDR to the decompressor via a linker symbol. >> ifneq ($(CONFIG_AUTO_ZRELADDR),y) >> LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR) >> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S >> index e8e1c866e413..dcc1afa60fb9 100644 >> --- a/arch/arm/boot/compressed/head.S >> +++ b/arch/arm/boot/compressed/head.S >> @@ -309,7 +309,8 @@ restart: adr r0, LC0 >> #ifndef CONFIG_ZBOOT_ROM >> /* malloc space is above the relocated stack (64k max) */ >> add sp, sp, r0 >> - add r10, sp, #0x10000 >> + ldr r10, =_malloc_size >> + add r10, r10, sp > > This says "locate _malloc_size in a literal pool somewhere, and load it > using a PC-relative offset". Are you sure that the literal pool is > sensibly located? > > Would it be better to use a definition for this? I've followed ZRELADDR way. I think both values should be handled the same way (it makes it easier to comprehend IMHO). Is there any reason not to? Should I change ZRELADDR for v2 too?
On Mon, Jun 01, 2020 at 04:56:40PM +0200, Lukasz Stelmach wrote: > It was <2020-06-01 pon 15:46>, when Russell King - ARM Linux admin wrote: > > On Mon, Jun 01, 2020 at 04:27:50PM +0200, Łukasz Stelmach wrote: > >> Move the definition of malloc pool size of the decompressor to > >> a single place. This value will be exposed later for kexec_file loader. > >> > >> Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com> > >> --- > >> arch/arm/boot/compressed/Makefile | 2 ++ > >> arch/arm/boot/compressed/head.S | 6 ++++-- > >> 2 files changed, 6 insertions(+), 2 deletions(-) > >> > >> diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile > >> index 9c11e7490292..b3594cd1588c 100644 > >> --- a/arch/arm/boot/compressed/Makefile > >> +++ b/arch/arm/boot/compressed/Makefile > >> @@ -125,6 +125,8 @@ KBSS_SZ = $(shell echo $$(($$($(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.
It was <2020-06-01 pon 16:10>, when Russell King - ARM Linux admin wrote: > 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 <l.stelmach@samsung.com> >> >> --- >> >> 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$$/+0x\1/p') )) ) >> >> LDFLAGS_vmlinux = --defsym _kernel_bss_size=$(KBSS_SZ) >> >> +# malloc pool size >> >> +LDFLAGS_vmlinux += --defsym _malloc_size=0x10000 >> >> # Supply ZRELADDR to the decompressor via a linker symbol. >> >> ifneq ($(CONFIG_AUTO_ZRELADDR),y) >> >> LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR) >> >> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S >> >> index e8e1c866e413..dcc1afa60fb9 100644 >> >> --- a/arch/arm/boot/compressed/head.S >> >> +++ b/arch/arm/boot/compressed/head.S >> >> @@ -309,7 +309,8 @@ restart: adr r0, LC0 >> >> #ifndef CONFIG_ZBOOT_ROM >> >> /* malloc space is above the relocated stack (64k max) */ >> >> add sp, sp, r0 >> >> - add r10, sp, #0x10000 >> >> + ldr r10, =_malloc_size >> >> + add r10, r10, sp >> > >> > This says "locate _malloc_size in a literal pool somewhere, and load it >> > using a PC-relative offset". Are you sure that the literal pool is >> > sensibly located? >> > >> > Would it be better to use a definition for this? >> >> I've followed ZRELADDR way. I think both values should be handled the >> same way (it makes it easier to comprehend IMHO). Is there any reason >> not to? Should I change ZRELADDR for v2 too? > > There's a good reason. ZRELADDR can be a constant that does not fit > into the ARMs immediate constants (8 bits of significant data plus > a multiple of a 2-bit shift), whereas the size of the malloc space > is guaranteed to fit. So, ZRELADDR has to use a literal load. > This doesn't. Indeed this is how TEXT_OFFSET works. Done.
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 9c11e7490292..b3594cd1588c 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -125,6 +125,8 @@ KBSS_SZ = $(shell echo $$(($$($(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 #else /* * With ZBOOT_ROM the bss/stack is non relocatable, @@ -623,7 +624,8 @@ not_relocated: mov r0, #0 */ mov r0, r4 mov r1, sp @ malloc space above stack - add r2, sp, #0x10000 @ 64k max + ldr r2, =_malloc_size @ 64k max + add r2, r2, sp mov r3, r7 bl decompress_kernel
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 <l.stelmach@samsung.com> --- arch/arm/boot/compressed/Makefile | 2 ++ arch/arm/boot/compressed/head.S | 6 ++++-- 2 files changed, 6 insertions(+), 2 deletions(-)