From: Vineet Gupta vgupta@synopsys.com
[ Upstream commit e494239a007e601448110ac304fe055951f9de3b ]
There's a hardware bug which affects the HSDK platform, triggered by micro-ops for auto-saving regfile on taken interrupt. The workaround is to inhibit autosave.
Signed-off-by: Vineet Gupta vgupta@synopsys.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arc/Kconfig | 8 +++++ arch/arc/include/asm/entry-arcv2.h | 54 ++++++++++++++++++++++++++++++ arch/arc/kernel/entry-arcv2.S | 4 ++- arch/arc/kernel/intc-arcv2.c | 2 ++ arch/arc/plat-hsdk/Kconfig | 1 + 5 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index ac69f307dcfe..74953e76a57d 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -420,6 +420,14 @@ config ARC_HAS_ACCL_REGS (also referred to as r58:r59). These can also be used by gcc as GPR so kernel needs to save/restore per process
+config ARC_IRQ_NO_AUTOSAVE + bool "Disable hardware autosave regfile on interrupts" + default n + help + On HS cores, taken interrupt auto saves the regfile on stack. + This is programmable and can be optionally disabled in which case + software INTERRUPT_PROLOGUE/EPILGUE do the needed work + endif # ISA_ARCV2
endmenu # "ARC CPU Configuration" diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h index 309f4e6721b3..225e7df2d8ed 100644 --- a/arch/arc/include/asm/entry-arcv2.h +++ b/arch/arc/include/asm/entry-arcv2.h @@ -17,6 +17,33 @@ ; ; Now manually save: r12, sp, fp, gp, r25
+#ifdef CONFIG_ARC_IRQ_NO_AUTOSAVE +.ifnc \called_from, exception + st.as r9, [sp, -10] ; save r9 in it's final stack slot + sub sp, sp, 12 ; skip JLI, LDI, EI + + PUSH lp_count + PUSHAX lp_start + PUSHAX lp_end + PUSH blink + + PUSH r11 + PUSH r10 + + sub sp, sp, 4 ; skip r9 + + PUSH r8 + PUSH r7 + PUSH r6 + PUSH r5 + PUSH r4 + PUSH r3 + PUSH r2 + PUSH r1 + PUSH r0 +.endif +#endif + #ifdef CONFIG_ARC_HAS_ACCL_REGS PUSH r59 PUSH r58 @@ -86,6 +113,33 @@ POP r59 #endif
+#ifdef CONFIG_ARC_IRQ_NO_AUTOSAVE +.ifnc \called_from, exception + POP r0 + POP r1 + POP r2 + POP r3 + POP r4 + POP r5 + POP r6 + POP r7 + POP r8 + POP r9 + POP r10 + POP r11 + + POP blink + POPAX lp_end + POPAX lp_start + + POP r9 + mov lp_count, r9 + + add sp, sp, 12 ; skip JLI, LDI, EI + ld.as r9, [sp, -10] ; reload r9 which got clobbered +.endif +#endif + .endm
/*------------------------------------------------------------------------*/ diff --git a/arch/arc/kernel/entry-arcv2.S b/arch/arc/kernel/entry-arcv2.S index cc558a25b8fa..562089d62d9d 100644 --- a/arch/arc/kernel/entry-arcv2.S +++ b/arch/arc/kernel/entry-arcv2.S @@ -209,7 +209,9 @@ restore_regs: ;####### Return from Intr #######
debug_marker_l1: - bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot + ; bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot + btst r0, STATUS_DE_BIT ; Z flag set if bit clear + bnz .Lintr_ret_to_delay_slot ; branch if STATUS_DE_BIT set
.Lisr_ret_fast_path: ; Handle special case #1: (Entry via Exception, Return via IRQ) diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c index 067ea362fb3e..cf18b3e5a934 100644 --- a/arch/arc/kernel/intc-arcv2.c +++ b/arch/arc/kernel/intc-arcv2.c @@ -49,11 +49,13 @@ void arc_init_IRQ(void)
*(unsigned int *)&ictrl = 0;
+#ifndef CONFIG_ARC_IRQ_NO_AUTOSAVE ictrl.save_nr_gpr_pairs = 6; /* r0 to r11 (r12 saved manually) */ ictrl.save_blink = 1; ictrl.save_lp_regs = 1; /* LP_COUNT, LP_START, LP_END */ ictrl.save_u_to_u = 0; /* user ctxt saved on kernel stack */ ictrl.save_idx_regs = 1; /* JLI, LDI, EI */ +#endif
WRITE_AUX(AUX_IRQ_CTRL, ictrl);
diff --git a/arch/arc/plat-hsdk/Kconfig b/arch/arc/plat-hsdk/Kconfig index 9356753c2ed8..c285a83cbf08 100644 --- a/arch/arc/plat-hsdk/Kconfig +++ b/arch/arc/plat-hsdk/Kconfig @@ -9,6 +9,7 @@ menuconfig ARC_SOC_HSDK bool "ARC HS Development Kit SOC" depends on ISA_ARCV2 select ARC_HAS_ACCL_REGS + select ARC_IRQ_NO_AUTOSAVE select CLK_HSDK select RESET_HSDK select MIGHT_HAVE_PCI