| Message ID | 20171117114143.26577-2-steve.capper@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Nov 17, 2017 at 11:41:42AM +0000, Steve Capper wrote: > Currently one resolves the location of the reserved_ttbr0 for PAN by > taking a positive offset from swapper_pg_dir. In a future patch we wish > to extend the swapper s.t. its size is determined at link time rather > than comile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low > level calculation. > > In this patch we re-arrange the order of the linker script s.t. instead > one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from > swapper_pg_dir. > > Signed-off-by: Steve Capper <steve.capper@arm.com> Looks sane to me. FWIW: Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > arch/arm64/include/asm/asm-uaccess.h | 6 +++--- > arch/arm64/include/asm/uaccess.h | 2 +- > arch/arm64/kernel/vmlinux.lds.S | 5 ++--- > 3 files changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h > index ecd9788cd298..95ba9865826a 100644 > --- a/arch/arm64/include/asm/asm-uaccess.h > +++ b/arch/arm64/include/asm/asm-uaccess.h > @@ -11,9 +11,9 @@ > */ > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > .macro __uaccess_ttbr0_disable, tmp1 > - mrs \tmp1, ttbr1_el1 // swapper_pg_dir > - add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir > - msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > + mrs \tmp1, ttbr1_el1 // swapper_pg_dir > + sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir > + msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > isb > .endm > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index fc0f9eb66039..66170fd4b58f 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -108,7 +108,7 @@ static inline void __uaccess_ttbr0_disable(void) > unsigned long ttbr; > > /* reserved_ttbr0 placed at the end of swapper_pg_dir */ > - ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; > + ttbr = read_sysreg(ttbr1_el1) - RESERVED_TTBR0_SIZE; > write_sysreg(ttbr, ttbr0_el1); > isb(); > } > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index fe56c268a7d9..6aa717582f6f 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -205,13 +205,12 @@ SECTIONS > . = ALIGN(PAGE_SIZE); > idmap_pg_dir = .; > . += IDMAP_DIR_SIZE; > - swapper_pg_dir = .; > - . += SWAPPER_DIR_SIZE; > - > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > reserved_ttbr0 = .; > . += RESERVED_TTBR0_SIZE; > #endif > + swapper_pg_dir = .; > + . += SWAPPER_DIR_SIZE; > > __pecoff_data_size = ABSOLUTE(. - __initdata_begin); > _end = .; > -- > 2.11.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Mon, Nov 20, 2017 at 04:25:22PM +0000, Mark Rutland wrote: > On Fri, Nov 17, 2017 at 11:41:42AM +0000, Steve Capper wrote: > > Currently one resolves the location of the reserved_ttbr0 for PAN by > > taking a positive offset from swapper_pg_dir. In a future patch we wish > > to extend the swapper s.t. its size is determined at link time rather > > than comile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low > > level calculation. > > > > In this patch we re-arrange the order of the linker script s.t. instead > > one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from > > swapper_pg_dir. > > > > Signed-off-by: Steve Capper <steve.capper@arm.com> > > Looks sane to me. FWIW: > > Acked-by: Mark Rutland <mark.rutland@arm.com> Thanks!
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h index ecd9788cd298..95ba9865826a 100644 --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -11,9 +11,9 @@ */ #ifdef CONFIG_ARM64_SW_TTBR0_PAN .macro __uaccess_ttbr0_disable, tmp1 - mrs \tmp1, ttbr1_el1 // swapper_pg_dir - add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir - msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 + mrs \tmp1, ttbr1_el1 // swapper_pg_dir + sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir + msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 isb .endm diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index fc0f9eb66039..66170fd4b58f 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -108,7 +108,7 @@ static inline void __uaccess_ttbr0_disable(void) unsigned long ttbr; /* reserved_ttbr0 placed at the end of swapper_pg_dir */ - ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; + ttbr = read_sysreg(ttbr1_el1) - RESERVED_TTBR0_SIZE; write_sysreg(ttbr, ttbr0_el1); isb(); } diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index fe56c268a7d9..6aa717582f6f 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -205,13 +205,12 @@ SECTIONS . = ALIGN(PAGE_SIZE); idmap_pg_dir = .; . += IDMAP_DIR_SIZE; - swapper_pg_dir = .; - . += SWAPPER_DIR_SIZE; - #ifdef CONFIG_ARM64_SW_TTBR0_PAN reserved_ttbr0 = .; . += RESERVED_TTBR0_SIZE; #endif + swapper_pg_dir = .; + . += SWAPPER_DIR_SIZE; __pecoff_data_size = ABSOLUTE(. - __initdata_begin); _end = .;
Currently one resolves the location of the reserved_ttbr0 for PAN by taking a positive offset from swapper_pg_dir. In a future patch we wish to extend the swapper s.t. its size is determined at link time rather than comile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low level calculation. In this patch we re-arrange the order of the linker script s.t. instead one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from swapper_pg_dir. Signed-off-by: Steve Capper <steve.capper@arm.com> --- arch/arm64/include/asm/asm-uaccess.h | 6 +++--- arch/arm64/include/asm/uaccess.h | 2 +- arch/arm64/kernel/vmlinux.lds.S | 5 ++--- 3 files changed, 6 insertions(+), 7 deletions(-)