| Message ID | 20230815004813.555115-17-vgupta@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | ARC updates | expand |
Hi Vineet, > Subject: [PATCH 16/20] ARC: entry: Add more common chores to > EXCEPTION_PROLOGUE > > THe high level structure of most ARC exception handlers is > 1. save regfile with EXCEPTION_PROLOGUE > 2. setup r0: EFA (not part of pt_regs) > 3. setup r1: pointer to pt_regs (SP) > 4. drop down to pure kernel mode (from exception) > 5. call the Linux "C" handler > > Remove the boiler plate code by moving #2, #3, #4 into #1. > > The exceptions to most exceptions are syscall Trap and Machine check > which don't do some of above for various reasons, so call a newly > introduced variant EXCEPTION_PROLOGUE_KEEP_AE (same as original > EXCEPTION_PROLOGUE) I'm observing the ARC700 (nSIM) system freeze after this patch. ... f0000000.serial: ttyS0 at MMIO 0xf0000000 (irq = 24, base_baud = 3125000) is a 16550A printk: console [ttyS0] enabled printk: console [ttyS0] enabled printk: bootconsole [uart8250] disabled printk: bootconsole [uart8250] disabled NET: Registered PF_PACKET protocol family NET: Registered PF_KEY protocol family clk: Disabling unused clocks Freeing unused kernel image (initmem) memory: 2856K This architecture does not have kernel memory protection. Run /init as init process > @@ -128,11 +123,6 @@ ENTRY(EV_PrivilegeV) > > EXCEPTION_PROLOGUE > > - lr r0, [efa] > - mov r1, sp > - > - FAKE_RET_FROM_EXCPN > - > bl do_privilege_fault > b ret_from_exception The same update is also required for the call_do_page_fault wrapper for ARcompact. Regards, Pavel
On 8/18/23 05:56, Pavel.Kozlov@synopsys.com wrote: > Hi Vineet, > >> Subject: [PATCH 16/20] ARC: entry: Add more common chores to >> EXCEPTION_PROLOGUE >> >> THe high level structure of most ARC exception handlers is >> 1. save regfile with EXCEPTION_PROLOGUE >> 2. setup r0: EFA (not part of pt_regs) >> 3. setup r1: pointer to pt_regs (SP) >> 4. drop down to pure kernel mode (from exception) >> 5. call the Linux "C" handler >> >> Remove the boiler plate code by moving #2, #3, #4 into #1. >> >> The exceptions to most exceptions are syscall Trap and Machine check >> which don't do some of above for various reasons, so call a newly >> introduced variant EXCEPTION_PROLOGUE_KEEP_AE (same as original >> EXCEPTION_PROLOGUE) > I'm observing the ARC700 (nSIM) system freeze after this patch. > > ... > f0000000.serial: ttyS0 at MMIO 0xf0000000 (irq = 24, base_baud = 3125000) is a 16550A > printk: console [ttyS0] enabled > printk: console [ttyS0] enabled > printk: bootconsole [uart8250] disabled > printk: bootconsole [uart8250] disabled > NET: Registered PF_PACKET protocol family > NET: Registered PF_KEY protocol family > clk: Disabling unused clocks > Freeing unused kernel image (initmem) memory: 2856K > This architecture does not have kernel memory protection. > Run /init as init process > >> @@ -128,11 +123,6 @@ ENTRY(EV_PrivilegeV) >> >> EXCEPTION_PROLOGUE >> >> - lr r0, [efa] >> - mov r1, sp >> - >> - FAKE_RET_FROM_EXCPN >> - >> bl do_privilege_fault >> b ret_from_exception > The same update is also required for the call_do_page_fault wrapper for ARcompact. Indeed I missed that part. -Vineet
diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h index a38ed505b3de..11b48ab39154 100644 --- a/arch/arc/include/asm/entry-arcv2.h +++ b/arch/arc/include/asm/entry-arcv2.h @@ -75,7 +75,7 @@ .endm /*------------------------------------------------------------------------*/ -.macro EXCEPTION_PROLOGUE +.macro EXCEPTION_PROLOGUE_KEEP_AE ; Before jumping to Exception Vector, hardware micro-ops did following: ; 1. SP auto-switched to kernel mode stack @@ -104,6 +104,16 @@ ; OUTPUT: r10 has ECR expected by EV_Trap .endm +.macro EXCEPTION_PROLOGUE + + EXCEPTION_PROLOGUE_KEEP_AE ; return ECR in r10 + + lr r0, [efa] + mov r1, sp + + FAKE_RET_FROM_EXCPN ; clobbers r9 +.endm + /*------------------------------------------------------------------------ * This macro saves the registers manually which would normally be autosaved * by hardware on taken interrupts. It is used by diff --git a/arch/arc/include/asm/entry-compact.h b/arch/arc/include/asm/entry-compact.h index 4e2ae82779ed..a0e760eb35a8 100644 --- a/arch/arc/include/asm/entry-compact.h +++ b/arch/arc/include/asm/entry-compact.h @@ -140,7 +140,7 @@ * * After this it is safe to call the "C" handlers *-------------------------------------------------------------*/ -.macro EXCEPTION_PROLOGUE +.macro EXCEPTION_PROLOGUE_KEEP_AE /* Need at least 1 reg to code the early exception prologue */ PROLOG_FREEUP_REG r9, @ex_saved_reg1 @@ -179,6 +179,16 @@ ; OUTPUT: r10 has ECR expected by EV_Trap .endm +.macro EXCEPTION_PROLOGUE + + EXCEPTION_PROLOGUE_KEEP_AE ; return ECR in r10 + + lr r0, [efa] + mov r1, sp + + FAKE_RET_FROM_EXCPN ; clobbers r9 +.endm + /*-------------------------------------------------------------- * Restore all registers used by system call or Exceptions * SP should always be pointing to the next free stack element diff --git a/arch/arc/kernel/entry-arcv2.S b/arch/arc/kernel/entry-arcv2.S index a7e6a2174187..2e49c81c8086 100644 --- a/arch/arc/kernel/entry-arcv2.S +++ b/arch/arc/kernel/entry-arcv2.S @@ -125,11 +125,6 @@ ENTRY(mem_service) EXCEPTION_PROLOGUE - lr r0, [efa] - mov r1, sp - - FAKE_RET_FROM_EXCPN - bl do_memory_error b ret_from_exception END(mem_service) @@ -138,11 +133,6 @@ ENTRY(EV_Misaligned) EXCEPTION_PROLOGUE - lr r0, [efa] ; Faulting Data address - mov r1, sp - - FAKE_RET_FROM_EXCPN - SAVE_CALLEE_SAVED_USER mov r2, sp ; callee_regs @@ -163,11 +153,6 @@ ENTRY(EV_TLBProtV) EXCEPTION_PROLOGUE - lr r0, [efa] ; Faulting Data address - mov r1, sp ; pt_regs - - FAKE_RET_FROM_EXCPN - mov blink, ret_from_exception b do_page_fault diff --git a/arch/arc/kernel/entry-compact.S b/arch/arc/kernel/entry-compact.S index 77f0090554c5..c218285cff87 100644 --- a/arch/arc/kernel/entry-compact.S +++ b/arch/arc/kernel/entry-compact.S @@ -256,16 +256,6 @@ ENTRY(EV_TLBProtV) EXCEPTION_PROLOGUE ; ECR returned in r10 - lr r0, [efa] ; Faulting Data address (not part of pt_regs saved above) - - ; Exception auto-disables further Intr/exceptions. - ; Re-enable them by pretending to return from exception - ; (so rest of handler executes in pure K mode) - - FAKE_RET_FROM_EXCPN - - mov r1, sp ; Handle to pt_regs - ;------ (5) Type of Protection Violation? ---------- ; ; ProtV Hardware Exception is triggered for Access Faults of 2 types diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 46582fbebcf2..089f6680518f 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -80,11 +80,6 @@ ENTRY(instr_service) EXCEPTION_PROLOGUE - lr r0, [efa] - mov r1, sp - - FAKE_RET_FROM_EXCPN - bl do_insterror_or_kprobe b ret_from_exception END(instr_service) @@ -95,7 +90,7 @@ END(instr_service) ENTRY(EV_MachineCheck) - EXCEPTION_PROLOGUE ; ECR returned in r10 + EXCEPTION_PROLOGUE_KEEP_AE ; ECR returned in r10 lr r0, [efa] mov r1, sp @@ -128,11 +123,6 @@ ENTRY(EV_PrivilegeV) EXCEPTION_PROLOGUE - lr r0, [efa] - mov r1, sp - - FAKE_RET_FROM_EXCPN - bl do_privilege_fault b ret_from_exception END(EV_PrivilegeV) @@ -144,11 +134,6 @@ ENTRY(EV_Extension) EXCEPTION_PROLOGUE - lr r0, [efa] - mov r1, sp - - FAKE_RET_FROM_EXCPN - bl do_extension_fault b ret_from_exception END(EV_Extension) @@ -229,7 +214,7 @@ trap_with_param: ENTRY(EV_Trap) - EXCEPTION_PROLOGUE + EXCEPTION_PROLOGUE_KEEP_AE lr r12, [efa]
THe high level structure of most ARC exception handlers is 1. save regfile with EXCEPTION_PROLOGUE 2. setup r0: EFA (not part of pt_regs) 3. setup r1: pointer to pt_regs (SP) 4. drop down to pure kernel mode (from exception) 5. call the Linux "C" handler Remove the boiler plate code by moving #2, #3, #4 into #1. The exceptions to most exceptions are syscall Trap and Machine check which don't do some of above for various reasons, so call a newly introduced variant EXCEPTION_PROLOGUE_KEEP_AE (same as original EXCEPTION_PROLOGUE) Signed-off-by: Vineet Gupta <vgupta@kernel.org> --- arch/arc/include/asm/entry-arcv2.h | 12 +++++++++++- arch/arc/include/asm/entry-compact.h | 12 +++++++++++- arch/arc/kernel/entry-arcv2.S | 15 --------------- arch/arc/kernel/entry-compact.S | 10 ---------- arch/arc/kernel/entry.S | 19 ++----------------- 5 files changed, 24 insertions(+), 44 deletions(-)