From aebd1fb45c622e9a2b06fb70665d084d3a8d6c78 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 22 Oct 2021 16:13:22 +1000 Subject: powerpc: flexible GPR range save/restore macros Introduce macros that operate on a (start, end) range of GPRs, which reduces lines of code and need to do mental arithmetic while reading the code. Signed-off-by: Nicholas Piggin Reviewed-by: Segher Boessenkool Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211022061322.2671178-1-npiggin@gmail.com --- arch/powerpc/boot/crt0.S | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) (limited to 'arch/powerpc/boot') diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S index 1d83966f5ef6..e8f10a599659 100644 --- a/arch/powerpc/boot/crt0.S +++ b/arch/powerpc/boot/crt0.S @@ -226,16 +226,19 @@ p_base: mflr r10 /* r10 now points to runtime addr of p_base */ #ifdef __powerpc64__ #define PROM_FRAME_SIZE 512 -#define SAVE_GPR(n, base) std n,8*(n)(base) -#define REST_GPR(n, base) ld n,8*(n)(base) -#define SAVE_2GPRS(n, base) SAVE_GPR(n, base); SAVE_GPR(n+1, base) -#define SAVE_4GPRS(n, base) SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base) -#define SAVE_8GPRS(n, base) SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base) -#define SAVE_10GPRS(n, base) SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base) -#define REST_2GPRS(n, base) REST_GPR(n, base); REST_GPR(n+1, base) -#define REST_4GPRS(n, base) REST_2GPRS(n, base); REST_2GPRS(n+2, base) -#define REST_8GPRS(n, base) REST_4GPRS(n, base); REST_4GPRS(n+4, base) -#define REST_10GPRS(n, base) REST_8GPRS(n, base); REST_2GPRS(n+8, base) + +.macro OP_REGS op, width, start, end, base, offset + .Lreg=\start + .rept (\end - \start + 1) + \op .Lreg,\offset+\width*.Lreg(\base) + .Lreg=.Lreg+1 + .endr +.endm + +#define SAVE_GPRS(start, end, base) OP_REGS std, 8, start, end, base, 0 +#define REST_GPRS(start, end, base) OP_REGS ld, 8, start, end, base, 0 +#define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) +#define REST_GPR(n, base) REST_GPRS(n, n, base) /* prom handles the jump into and return from firmware. The prom args pointer is loaded in r3. */ @@ -246,9 +249,7 @@ prom: stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */ SAVE_GPR(2, r1) - SAVE_GPR(13, r1) - SAVE_8GPRS(14, r1) - SAVE_10GPRS(22, r1) + SAVE_GPRS(13, 31, r1) mfcr r10 std r10,8*32(r1) mfmsr r10 @@ -283,9 +284,7 @@ prom: /* Restore other registers */ REST_GPR(2, r1) - REST_GPR(13, r1) - REST_8GPRS(14, r1) - REST_10GPRS(22, r1) + REST_GPRS(13, 31, r1) ld r10,8*32(r1) mtcr r10 -- cgit v1.2.3-70-g09d2 From 9cbbe6bae938dd335a5092b0ce41f88cb39ba40c Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Fri, 17 Dec 2021 16:14:00 -0600 Subject: powerpc/dts: Remove "spidev" nodes "spidev" is not a real device, but a Linux implementation detail. It has never been documented either. The kernel has WARNed on the use of it for over 6 years. Time to remove its usage from the tree. Signed-off-by: Rob Herring Reviewed-by: Mark Brown Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211217221400.3667133-1-robh@kernel.org --- arch/powerpc/boot/dts/digsy_mtc.dts | 8 -------- arch/powerpc/boot/dts/o2d.dtsi | 6 ------ 2 files changed, 14 deletions(-) (limited to 'arch/powerpc/boot') diff --git a/arch/powerpc/boot/dts/digsy_mtc.dts b/arch/powerpc/boot/dts/digsy_mtc.dts index 57024a4c1e7d..dfaf974c0ce6 100644 --- a/arch/powerpc/boot/dts/digsy_mtc.dts +++ b/arch/powerpc/boot/dts/digsy_mtc.dts @@ -25,14 +25,6 @@ status = "disabled"; }; - spi@f00 { - msp430@0 { - compatible = "spidev"; - spi-max-frequency = <32000>; - reg = <0>; - }; - }; - psc@2000 { // PSC1 status = "disabled"; }; diff --git a/arch/powerpc/boot/dts/o2d.dtsi b/arch/powerpc/boot/dts/o2d.dtsi index b55a9e5bd828..7e52509fa506 100644 --- a/arch/powerpc/boot/dts/o2d.dtsi +++ b/arch/powerpc/boot/dts/o2d.dtsi @@ -34,12 +34,6 @@ #address-cells = <1>; #size-cells = <0>; cell-index = <0>; - - spidev@0 { - compatible = "spidev"; - spi-max-frequency = <250000>; - reg = <0>; - }; }; psc@2200 { // PSC2 -- cgit v1.2.3-70-g09d2 From a3ad84da076009c94969fa97f604257667e2980f Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Tue, 21 Dec 2021 16:58:59 +1100 Subject: powerpc/toc: Future proof kernel toc This patch future-proofs the kernel against linker changes that might put the toc pointer at some location other than .got+0x8000, by replacing __toc_start+0x8000 with .TOC. throughout. If the kernel's idea of the toc pointer doesn't agree with the linker, bad things happen. prom_init.c code relocating its toc is also changed so that a symbolic __prom_init_toc_start toc-pointer relative address is calculated rather than assuming that it is always at toc-pointer - 0x8000. The length calculations loading values from the toc are also avoided. It's a little incestuous to do that with unreloc_toc picking up adjusted values (which is fine in practice, they both adjust by the same amount if all goes well). I've also changed the way .got is aligned in vmlinux.lds and zImage.lds, mostly so that dumping out section info by objdump or readelf plainly shows the alignment is 256. This linker script feature was added 2005-09-27, available in FSF binutils releases from 2.17 onwards. Should be safe to use in the kernel, I think. Finally, put *(.got) before the prom_init.o entry which only needs *(.toc), so that the GOT header goes in the correct place. I don't believe this makes any difference for the kernel as it would for dynamic objects being loaded by ld.so. That change is just to stop lusers who blindly copy kernel scripts being led astray. Of course, this change needs the prom_init.c changes. Some notes on .toc and .got. .toc is a compiler generated section of addresses. .got is a linker generated section of addresses, generally built when the linker sees R_*_*GOT* relocations. In the case of powerpc64 ld.bfd, there are multiple generated .got sections, one per input object file. So you can somewhat reasonably write in a linker script an input section statement like *prom_init.o(.got .toc) to mean "the .got and .toc section for files matching *prom_init.o". On other architectures that doesn't make sense, because the linker generally has just one .got section. Even on powerpc64, note well that the GOT entries for prom_init.o may be merged with GOT entries from other objects. That means that if prom_init.o references, say, _end via some GOT relocation, and some other object also references _end via a GOT relocation, the GOT entry for _end may be in the range __prom_init_toc_start to __prom_init_toc_end and if the kernel does something special to GOT/TOC entries in that range then the value of _end as seen by objects other than prom_init.o will be affected. On the other hand the GOT entry for _end may not be in the range __prom_init_toc_start to __prom_init_toc_end. Which way it turns out is deterministic but a detail of linker operation that should not be relied on. A feature of ld.bfd is that input .toc (and .got) sections matching one linker input section statement may be sorted, to put entries used by small-model code first, near the toc base. This is why scripts for powerpc64 normally use *(.got .toc) rather than *(.got) *(.toc), since the first form allows more freedom to sort. Another feature of ld.bfd is that indirect addressing sequences using the GOT/TOC may be edited by the linker to relative addressing. In many cases relative addressing would be emitted by gcc for -mcmodel=medium if you appropriately decorate variable declarations with non-default visibility. The original patch is here: https://lore.kernel.org/linuxppc-dev/20210310034813.GM6042@bubble.grove.modra.org/ Signed-off-by: Alan Modra [aik: removed non-relocatable which is gone in 24d33ac5b8ffb] [aik: added <=2.24 check] [aik: because of llvm-as, kernel_toc_addr() uses "mr" instead of global register variable] Signed-off-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211221055904.555763-2-aik@ozlabs.ru --- arch/powerpc/Makefile | 5 +++-- arch/powerpc/boot/crt0.S | 2 +- arch/powerpc/boot/zImage.lds.S | 7 ++----- arch/powerpc/include/asm/sections.h | 16 ++++++++-------- arch/powerpc/kernel/head_64.S | 2 +- arch/powerpc/kernel/vmlinux.lds.S | 8 +++----- 6 files changed, 18 insertions(+), 22 deletions(-) (limited to 'arch/powerpc/boot') diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index e02568f17334..e9aa4e8b07dd 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -445,10 +445,11 @@ PHONY += checkbin # Check toolchain versions: # - gcc-4.6 is the minimum kernel-wide version so nothing required. checkbin: - @if test "x${CONFIG_CPU_LITTLE_ENDIAN}" = "xy" \ - && $(LD) --version | head -1 | grep ' 2\.24$$' >/dev/null ; then \ + @if test "x${CONFIG_LD_IS_LLD}" != "xy" -a \ + "x$(call ld-ifversion, -le, 22400, y)" = "xy" ; then \ echo -n '*** binutils 2.24 miscompiles weak symbols ' ; \ echo 'in some circumstances.' ; \ + echo '*** binutils 2.23 do not define the TOC symbol ' ; \ echo -n '*** Please use a different binutils version.' ; \ false ; \ fi diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S index e8f10a599659..feadee18e271 100644 --- a/arch/powerpc/boot/crt0.S +++ b/arch/powerpc/boot/crt0.S @@ -28,7 +28,7 @@ p_etext: .8byte _etext p_bss_start: .8byte __bss_start p_end: .8byte _end -p_toc: .8byte __toc_start + 0x8000 - p_base +p_toc: .8byte .TOC. - p_base p_dyn: .8byte __dynamic_start - p_base p_rela: .8byte __rela_dyn_start - p_base p_prom: .8byte 0 diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S index d6f072865627..d65cd55a6f38 100644 --- a/arch/powerpc/boot/zImage.lds.S +++ b/arch/powerpc/boot/zImage.lds.S @@ -36,12 +36,9 @@ SECTIONS } #ifdef CONFIG_PPC64_BOOT_WRAPPER - . = ALIGN(256); - .got : + .got : ALIGN(256) { - __toc_start = .; - *(.got) - *(.toc) + *(.got .toc) } #endif diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 79cb7a25a5fb..38f79e42bf3c 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -25,16 +25,16 @@ extern char start_virt_trampolines[]; extern char end_virt_trampolines[]; #endif +/* + * This assumes the kernel is never compiled -mcmodel=small or + * the total .toc is always less than 64k. + */ static inline unsigned long kernel_toc_addr(void) { - /* Defined by the linker, see vmlinux.lds.S */ - extern unsigned long __toc_start; - - /* - * The TOC register (r2) points 32kB into the TOC, so that 64kB of - * the TOC can be addressed using a single machine instruction. - */ - return (unsigned long)(&__toc_start) + 0x8000UL; + unsigned long toc_ptr; + + asm volatile("mr %0, 2" : "=r" (toc_ptr)); + return toc_ptr; } static inline int overlaps_interrupt_vector_text(unsigned long start, diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index f17ae2083733..a08c050ff645 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -904,7 +904,7 @@ _GLOBAL(relative_toc) blr .balign 8 -p_toc: .8byte __toc_start + 0x8000 - 0b +p_toc: .8byte .TOC. - 0b /* * This is where the main kernel code starts. diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index dfc3f39d365f..2bcca818136a 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -337,15 +337,13 @@ SECTIONS *(.branch_lt) } - . = ALIGN(256); - .got : AT(ADDR(.got) - LOAD_OFFSET) { - __toc_start = .; + .got : AT(ADDR(.got) - LOAD_OFFSET) ALIGN(256) { + *(.got) #ifndef CONFIG_RELOCATABLE __prom_init_toc_start = .; - arch/powerpc/kernel/prom_init.o*(.toc .got) + arch/powerpc/kernel/prom_init.o*(.toc) __prom_init_toc_end = .; #endif - *(.got) *(.toc) } #endif -- cgit v1.2.3-70-g09d2