kernel.git/arch/powerpc/include/asm/ppc_asm.h, branch linux-5.13.y

powerpc/64e/interrupt: use new interrupt return

2021-04-14T13:04:20Z

Update the new C and asm interrupt return code to account for 64e specifics, switch over to use it. The now-unused old ret_from_except code, that was moved to 64e after the 64s conversion, is removed. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210316104206.407354-5-npiggin@gmail.com

powerpc/32: Entry cpu time accounting in C

2021-03-29T02:22:04Z

There is no need for this to be in asm, use the new interrupt entry wrapper. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/daca4c3e05cdfe54d237162a0718b3aaca897662.1615552866.git.christophe.leroy@csgroup.eu

powerpc/64: entry cpu time accounting in C

2021-02-08T13:10:49Z

There is no need for this to be in asm, use the new interrupt entry wrapper. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210130130852.2952424-39-npiggin@gmail.com

powerpc/vdso: Fix DOTSYM for 32-bit LE VDSO

2020-12-21T11:06:26Z

Skirmisher reported on IRC that the 32-bit LE VDSO was hanging. This turned out to be due to a branch to self in eg. __kernel_gettimeofday. Looking at the disassembly with objdump -dR shows why: 00000528 <__kernel_gettimeofday>: 528: f0 ff 21 94 stwu r1,-16(r1) 52c: a6 02 08 7c mflr r0 530: f0 ff 21 94 stwu r1,-16(r1) 534: 14 00 01 90 stw r0,20(r1) 538: 05 00 9f 42 bcl 20,4*cr7+so,53c <__kernel_gettimeofday+0x14> 53c: a6 02 a8 7c mflr r5 540: ff ff a5 3c addis r5,r5,-1 544: c4 fa a5 38 addi r5,r5,-1340 548: f0 00 a5 38 addi r5,r5,240 54c: 01 00 00 48 bl 54c <__kernel_gettimeofday+0x24> 54c: R_PPC_REL24 .__c_kernel_gettimeofday Because we don't process relocations for the VDSO, this branch remains a branch from 0x54c to 0x54c. With the preceding patch to prohibit R_PPC_REL24 relocations, we instead get a build failure: 0000054c R_PPC_REL24 .__c_kernel_gettimeofday 00000598 R_PPC_REL24 .__c_kernel_clock_gettime 000005e4 R_PPC_REL24 .__c_kernel_clock_gettime64 00000630 R_PPC_REL24 .__c_kernel_clock_getres 0000067c R_PPC_REL24 .__c_kernel_time arch/powerpc/kernel/vdso32/vdso32.so.dbg: dynamic relocations are not supported The root cause is that we're branching to `.__c_kernel_gettimeofday`. But this is 32-bit LE code, which doesn't use function descriptors, so there are no dot symbols. The reason we're trying to branch to a dot symbol is because we're using the DOTSYM macro, but the ifdefs we use to define the DOTSYM macro do not currently work for 32-bit LE. So like previous commits we need to differentiate if the current compilation unit is 64-bit, rather than the kernel as a whole. ie. switch from CONFIG_PPC64 to __powerpc64__. With that fixed 32-bit LE code gets the empty version of DOTSYM, which just resolves to the original symbol name, leading to a direct branch and no relocations: 000003f8 <__kernel_gettimeofday>: 3f8: f0 ff 21 94 stwu r1,-16(r1) 3fc: a6 02 08 7c mflr r0 400: f0 ff 21 94 stwu r1,-16(r1) 404: 14 00 01 90 stw r0,20(r1) 408: 05 00 9f 42 bcl 20,4*cr7+so,40c <__kernel_gettimeofday+0x14> 40c: a6 02 a8 7c mflr r5 410: ff ff a5 3c addis r5,r5,-1 414: f4 fb a5 38 addi r5,r5,-1036 418: f0 00 a5 38 addi r5,r5,240 41c: 85 06 00 48 bl aa0 <__c_kernel_gettimeofday> Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.") Reported-by: "Will Springer " Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201218111619.1206391-3-mpe@ellerman.id.au

powerpc/vdso: Prepare for switching VDSO to generic C implementation.

2020-12-03T14:01:10Z

Prepare for switching VDSO to generic C implementation in following patch. Here, we: - Prepare the helpers to call the C VDSO functions - Prepare the required callbacks for the C VDSO functions - Prepare the clocksource.h files to define VDSO_ARCH_CLOCKMODES - Add the C trampolines to the generic C VDSO functions powerpc is a bit special for VDSO as well as system calls in the way that it requires setting CR SO bit which cannot be done in C. Therefore, entry/exit needs to be performed in ASM. Implementing __arch_get_vdso_data() would clobber the link register, requiring the caller to save it. As the ASM calling function already has to set a stack frame and saves the link register before calling the C vdso function, retriving the vdso data pointer there is lighter. Implement __arch_vdso_capable() and always return true. Provide vdso_shift_ns(), as the generic x >> s gives the following bad result: 18: 35 25 ff e0 addic. r9,r5,-32 1c: 41 80 00 10 blt 2c 20: 7c 64 4c 30 srw r4,r3,r9 24: 38 60 00 00 li r3,0 ... 2c: 54 69 08 3c rlwinm r9,r3,1,0,30 30: 21 45 00 1f subfic r10,r5,31 34: 7c 84 2c 30 srw r4,r4,r5 38: 7d 29 50 30 slw r9,r9,r10 3c: 7c 63 2c 30 srw r3,r3,r5 40: 7d 24 23 78 or r4,r9,r4 In our case the shift is always <= 32. In addition, the upper 32 bits of the result are likely nul. Lets GCC know it, it also optimises the following calculations. With the patch, we get: 0: 21 25 00 20 subfic r9,r5,32 4: 7c 69 48 30 slw r9,r3,r9 8: 7c 84 2c 30 srw r4,r4,r5 c: 7d 24 23 78 or r4,r9,r4 10: 7c 63 2c 30 srw r3,r3,r5 Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201126131006.2431205-6-mpe@ellerman.id.au

powerpc: Remove RFI macro

2020-11-19T05:56:55Z

RFI macro is just there to add an infinite loop past rfi in order to avoid prefetch on 40x in half a dozen of places in entry_32 and head_32. Those places are already full of #ifdefs, so just add a few more to explicitely show those loops and remove RFI. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f7e9cb9e9240feec63cb330abf40b67d1aad852f.1604854583.git.christophe.leroy@csgroup.eu

powerpc/64s: Replace RFI by RFI_TO_KERNEL and remove RFI

2020-11-19T05:56:54Z

In head_64.S, we have two places using RFI to return to kernel. Use RFI_TO_KERNEL instead. They are the two only places using RFI on book3s/64, so the RFI macro can go away. Signed-off-by: Christophe Leroy Acked-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/7719261b0a0d2787772339484c33eb809723bca7.1604854583.git.christophe.leroy@csgroup.eu

powerpc: Remove support for PowerPC 601

2020-10-08T10:17:13Z

PowerPC 601 has been retired. Remove all associated specific code. CPU_FTRS_PPC601 has CPU_FTR_COHERENT_ICACHE and CPU_FTR_COMMON. CPU_FTR_COMMON is already present via other CPU_FTRS. None of the remaining CPU selects CPU_FTR_COHERENT_ICACHE. So CPU_FTRS_PPC601 can be removed from the possible features, hence can be removed completely. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/60b725d55e21beec3335175c20b77903ff98284f.1601362098.git.christophe.leroy@csgroup.eu

powerpc: Drop SYNC_601() ISYNC_601() and SYNC()

2020-10-08T10:17:13Z

Those macros are now empty at all time. Drop them. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/7990bb63fc53e460bfa94f8040184881d9e6fbc3.1601362098.git.christophe.leroy@csgroup.eu

powerpc: Remove CONFIG_PPC601_SYNC_FIX

2020-10-08T10:17:13Z

This config option isn't in any defconfig. The very first versions of Powerpc 601 have a bug which requires additional sync before and/or after some instructions. This was more than 25 years ago and time has come to retire those buggy versions of the 601 from the kernel. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/55b46bff16705b1ae7bf0a60ccd522b1010ebf75.1601362098.git.christophe.leroy@csgroup.eu