drivers: soc: cal-if: Prevent optimization of structs on fvmap_copy_from_sram
Newer versions of Clang tend to apply heavier optimizations than GCC, especially if -mcpu is set. Because we are applying optimizations to the LITTLE core (see b92e1e70898f515646142736df8d72c43e97e251) kernel panics during boot, citing inability to access memory regions on fvmap_init.
<6>[ 0.664609] [0: swapper/0: 1] fvmap_init:fvmap initialize 0000000000000000
<0>[ 0.664625] [0: swapper/0: 1] Unable to handle kernel paging request at virtual address ffffff800b2f2402
<2>[ 0.664640] [0: swapper/0: 1] sec_debug_set_extra_info_fault = KERN / 0xffffff800b2f2402
<6>[ 0.664657] [0: swapper/0: 1] search_item_by_key: (FTYPE) extra_info is not ready
<2>[ 0.664666] [0: swapper/0: 1] set_item_val: fail to find FTYPE
<6>[ 0.664680] [0: swapper/0: 1] search_item_by_key: (FAULT) extra_info is not ready
<2>[ 0.664688] [0: swapper/0: 1] set_item_val: fail to find FAULT
<6>[ 0.664702] [0: swapper/0: 1] search_item_by_key: (PC) extra_info is not ready
<2>[ 0.664710] [0: swapper/0: 1] set_item_val: fail to find PC
<6>[ 0.664724] [0: swapper/0: 1] search_item_by_key: (LR) extra_info is not ready
<2>[ 0.664732] [0: swapper/0: 1] set_item_val: fail to find LR
<1>[ 0.664746] [0: swapper/0: 1] Mem abort info:
<1>[ 0.664760] [0: swapper/0: 1] Exception class = DABT (current EL), IL = 32 bits
<1>[ 0.664774] [0: swapper/0: 1] SET = 0, FnV = 0
<1>[ 0.664787] [0: swapper/0: 1] EA = 0, S1PTW = 0
<1>[ 0.664799] [0: swapper/0: 1] Data abort info:
<1>[ 0.664814] [0: swapper/0: 1] ISV = 0, ISS = 0x00000021
<1>[ 0.664828] [0: swapper/0: 1] CM = 0, WnR = 0
<1>[ 0.664842] [0: swapper/0: 1] swapper pgtable: 4k pages, 39-bit VAs, pgd = ffffff800a739000
<1>[ 0.664856] [0: swapper/0: 1] [ffffff800b2f2402] *pgd=000000097cdfe003, *pud=000000097cdfe003, *pmd=00000009742a9003, *pte=00e800000204b707
<0>[ 0.664884] [0: swapper/0: 1] Internal error: Oops: 96000021 [#1] PREEMPT SMP
<4>[ 0.664899] [0: swapper/0: 1] Modules linked in:
<0>[ 0.664916] [0: swapper/0: 1] Process swapper/0 (pid: 1, stack limit = 0xffffff80081a8000)
<0>[ 0.664936] [0: swapper/0: 1] debug-snapshot: core register saved(CPU:0)
<0>[ 0.664950] [0: swapper/0: 1] L2ECTLR_EL1: 0000000000000007
<0>[ 0.664959] [0: swapper/0: 1] L2ECTLR_EL1 valid_bit(30) is NOT set (0x0)
<0>[ 0.664978] [0: swapper/0: 1] CPUMERRSR: 0000000008000001, L2MERRSR: 0000000010200c00
<0>[ 0.664992] [0: swapper/0: 1] CPUMERRSR valid_bit(31) is NOT set (0x0)
<0>[ 0.665006] [0: swapper/0: 1] L2MERRSR valid_bit(31) is NOT set (0x0)
<0>[ 0.665020] [0: swapper/0: 1] debug-snapshot: context saved(CPU:0)
<6>[ 0.665088] [0: swapper/0: 1] debug-snapshot: item - log_kevents is disabled
<6>[ 0.665112] [0: swapper/0: 1] TIF_FOREIGN_FPSTATE: 0, FP/SIMD depth 0, cpu: 0
<4>[ 0.665130] [0: swapper/0: 1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.113 - Fresh Core-user #1
<4>[ 0.665144] [0: swapper/0: 1] Hardware name: Samsung A50 LTN OPEN rev04 board based on Exynos9610 (DT)
<4>[ 0.665160] [0: swapper/0: 1] task: ffffffc8f4ce8000 task.stack: ffffff80081a8000
<4>[ 0.665180] [0: swapper/0: 1] PC is at fvmap_init+0xac/0x2c8
<4>[ 0.665195] [0: swapper/0: 1] LR is at fvmap_init+0x70/0x2c8
<4>[ 0.665211] [0: swapper/0: 1] pc : [<ffffff80085e12b8>] lr : [<ffffff80085e127c>] pstate: 20400145
<4>[ 0.665225] [0: swapper/0: 1] sp : ffffff80081abb80
<4>[ 0.665238] [0: swapper/0: 1] x29: ffffff80081abbb0 x28: 0000000000000000
<4>[ 0.665256] [0: swapper/0: 1] x27: ffffff8009efc000 x26: 0000000000000000
<4>[ 0.665273] [0: swapper/0: 1] x25: ffffff800b2e5970 x24: ffffff8008fa7222
<4>[ 0.665291] [0: swapper/0: 1] x23: ffffff800b2e5a60 x22: ffffff8009efb000
<4>[ 0.665307] [0: swapper/0: 1] x21: ffffffc8f3480000 x20: ffffff800b2e0000
<4>[ 0.665324] [0: swapper/0: 1] x19: ffffff800b2f2400 x18: 0000000000000000
<4>[ 0.665341] [0: swapper/0: 1] x17: ffffff8009bff23c x16: 0000000000000000
<4>[ 0.665358] [0: swapper/0: 1] x15: 00000000000000c6 x14: 0000000000000054
<4>[ 0.665375] [0: swapper/0: 1] x13: 000000000000d7b8 x12: 0000000000000000
<4>[ 0.665392] [0: swapper/0: 1] x11: 0000000000000000 x10: ffffffc8f3480000
<4>[ 0.665409] [0: swapper/0: 1] x9 : ffffff800b2f2400 x8 : 0000000000000000
<4>[ 0.665426] [0: swapper/0: 1] x7 : 5b20205d39303634 x6 : ffffffc0117d09b7
<4>[ 0.665443] [0: swapper/0: 1] x5 : 0000000000000001 x4 : 000000000000000c
<4>[ 0.665459] [0: swapper/0: 1] x3 : 0000000000000a30 x2 : ffffffffffffffce
<4>[ 0.665476] [0: swapper/0: 1] x1 : 000000000b040000 x0 : 000000000000000a
Since we need these optimizations for performance reasons, the only way to resolve this is to solve the issue. Samsung already did something similar to cal-if before.
We only needed to make fvmap_header/header volatile and has been tested to work.
Signed-off-by: John Vincent <git@tensevntysevn.cf>
Change-Id: Ic419135d4a80cbe15f0fa71dc59cc6efa73d6141
77940d8531