refactor(cpus): convert Neoverse V2 to framework

For V2, this involves replacing:
  - The reset_func with the standard cpu_reset_func_{start,end}
    to apply errata automatically
  - The <cpu>_errata_report with the errata_report_shim to
    report errata automatically

And for each erratum:
  - The prologue with the workaround_<type>_start to do the checks and
    framework registration automatically at reset or runtime
  - The epilogue with the workaround_<type>_end
  - The checker function with the check_erratum_<type> to check whether
    the erratum applies on the revision of the CPU.

It is important to note that the errata workaround sequences remain
unchanged and preserve their git blame.

Testing was conducted by:

 * Manual comparison of disassembly of converted functions with non-
   converted functions

   aarch64-none-elf-objdump -D <trusted-firmware-a with conversion>/build/fvp/release/bl31/bl31.elf
     vs
   aarch64-none-elf-objdump -D <trusted-firmware-a clean repo>/build/fvp/release/bl31/bl31.elf

 * Build for release with all errata flags enabled and run default tftf
   tests

   CROSS_COMPILE=aarch64-none-elf- make PLAT=fvp  CTX_INCLUDE_AARCH32_REGS=0 \
   HW_ASSISTED_COHERENCY=1 USE_COHERENT_MEM=0 \
   BL33=./../tf-a-tests/build/fvp/debug/tftf.bin \
   ERRATA_V2_2801372 WORKAROUND_CVE_2022_23960=1 ERRATA_ABI_SUPPORT=1 all fip

 * Build for debug with all errata enabled and step through ArmDS
   at reset to ensure all functions are entered.

Change-Id: Ic968844d6aabea3867189d747769ced8faa87e56
Signed-off-by: Moritz Fischer <moritzf@google.com>
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>

lib/cpus/aarch64/neoverse_v2.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2023, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -22,6 +22,26 @@
 #error "Neoverse V2 supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+workaround_runtime_start neoverse_v2, ERRATUM(2801372), ERRATA_V2_2801372
+	/* dsb before isb of power down sequence */
+	dsb	sy
+workaround_runtime_end neoverse_v2, ERRATUM(2801372), ERRATA_V2_2801372
+
+check_erratum_ls neoverse_v2, ERRATUM(2801372), CPU_REV(0, 1)
+
+workaround_reset_start neoverse_v2, CVE(2022,23960), WORKAROUND_CVE_2022_23960
+#if IMAGE_BL31
+	/*
+	 * The Neoverse-V2 generic vectors are overridden to apply errata
+         * mitigation on exception entry from lower ELs.
+	 */
+	adr	x0, wa_cve_vbar_neoverse_v2
+	msr	vbar_el3, x0
+#endif /* IMAGE_BL31 */
+workaround_reset_end neoverse_v2, CVE(2022,23960)
+
+check_erratum_chosen neoverse_v2, CVE(2022, 23960), WORKAROUND_CVE_2022_23960
+
 #if WORKAROUND_CVE_2022_23960
 	wa_cve_2022_23960_bhb_vector_table NEOVERSE_V2_BHB_LOOP_COUNT, neoverse_v2
 #endif /* WORKAROUND_CVE_2022_23960 */
@@ -38,87 +58,19 @@ func neoverse_v2_core_pwr_dwn
 	mrs	x0, NEOVERSE_V2_CPUPWRCTLR_EL1
 	orr	x0, x0, #NEOVERSE_V2_CPUPWRCTLR_EL1_CORE_PWRDN_BIT
 	msr	NEOVERSE_V2_CPUPWRCTLR_EL1, x0
-#if ERRATA_V2_2801372
+
-	mov	x15, x30
+	apply_erratum neoverse_v2, ERRATUM(2801372), ERRATA_V2_2801372
-	bl	cpu_get_rev_var
+
-	bl	errata_neoverse_v2_2801372_wa
-	mov	x30, x15
-#endif /* ERRATA_V2_2801372 */
 	isb
 	ret
 endfunc neoverse_v2_core_pwr_dwn
 
-func check_errata_cve_2022_23960
+cpu_reset_func_start neoverse_v2
-#if WORKAROUND_CVE_2022_23960
-	mov	x0, #ERRATA_APPLIES
-#else
-	mov	x0, #ERRATA_MISSING
-#endif
-	ret
-endfunc check_errata_cve_2022_23960
-
-	/* ----------------------------------------------------
-	 * Errata Workaround for Neoverse V2 Errata #2801372
-	 * This applies to revisions <= r0p1 and is fixed in r0p2.
-	 * x0: variant[4:7] and revision[0:3] of current cpu.
-	 * Shall clobber: x0-x17
-	 * ----------------------------------------------------
-	 */
-func errata_neoverse_v2_2801372_wa
-	mov	x17, x30
-	bl	check_errata_2801372
-	cbz	x0, 1f
-
-	/* dsb before isb of power down sequence */
-	dsb	sy
-1:
-	ret	x17
-endfunc errata_neoverse_v2_2801372_wa
-
-func check_errata_2801372
-	/* Applies to all revisions <= r0p1 */
-	mov	x1, #0x01
-	b	cpu_rev_var_ls
-endfunc check_errata_2801372
-
-func neoverse_v2_reset_func
 	/* Disable speculative loads */
 	msr	SSBS, xzr
+cpu_reset_func_end neoverse_v2
 
-#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+errata_report_shim neoverse_v2
-	/*
-	 * The Neoverse V2 vectors are overridden to apply
-	 * errata mitigation on exception entry from lower ELs.
-	 */
-	adr	x0, wa_cve_vbar_neoverse_v2
-	msr	vbar_el3, x0
-#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
-	isb
-	ret
-endfunc neoverse_v2_reset_func
-
-#if REPORT_ERRATA
-/*
- * Errata printing function for Neoverse V2. Must follow AAPCS.
- */
-func neoverse_v2_errata_report
-	stp	x8, x30, [sp, #-16]!
-
-	bl	cpu_get_rev_var
-	mov	x8, x0
-
-	/*
-	 * Report all errata. The revision-variant information is passed to
-	 * checking functions of each errata.
-	 */
-	report_errata WORKAROUND_CVE_2022_23960, neoverse_v2, cve_2022_23960
-	report_errata ERRATA_V2_2801372, neoverse_v2, 2801372
-
-	ldp	x8, x30, [sp], #16
-	ret
-endfunc neoverse_v2_errata_report
-#endif
-
 	/* ---------------------------------------------
 	 * This function provides Neoverse V2-
 	 * specific register information for crash